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FERTILIZERS: 


THEIR 


=    Source,  Purchase#Use 


BY 


CARROLL  B.  SMITH 


SECOND  EDITION 


THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

LOS  ANGELES 


4*<1*r      /f/Z- 


Digitized  by  the  Internet  Archive 

in  2007  with  funding  from 

Microsoft  Corporation 


http://www.archive.org/details/fertilizerstheirOOsmitiala 


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FLRTILIZLR5: 


■Their- 


Source,  Purchase,  and  Use 

Written  for  the  Use  of   Farmers 

and  Fruit  Growers,  With  Special 

Reference  to  Citrus  Culture.  ::    :: 

By 

CARROLL  B.  5MITH 


SECOND  EDITION 

Revised  and  Enlarged 


REDLANDS.  CALIFORNIA: 
CITROGRAPH     BOOK     PRESS 

19  11 


COPYRIGHTED     1911 

BY 
CARROLL     B.     SMITH 


9/1 


Sfc+3'Jf 


TO  THE  READER. 

This  work  is  designed  expressly  for  those 
who  are  forced  to  use  fertilizers  and  yet  have 
not  the  time  to  investigate  the  subject  as  they 
would  like  to.  It  is  intended  to  be  brief  and 
suggestive  of  thought  to  the  reader  rather 
than  complete  and  final. 

Technicalities  are  avoided  and  illustrations 
simplified  as  much  as  possible. 

All  the  facts  and  deductions  contained  are 
based  on  the  highest  authorities  on  the  sub- 
jects mentioned,  and  largely  on  the  results  of 
actual  experience  in  California. 

The  author  hopes  that  the  matter  here  given 
will  aid  the  farmer  to  choose  and  purchase  his 
fertilizers  most  wisely,  and  help  him  to  get  the 
best  possible  results  from  their  use.  There  is 
no  final  authority  in  Nature.  Every  farmer's 
problems  are  his  own  and  he  must  do  his  own 
thinking.  The  author  has  tried  to  present 
only  the  well  established  facts  and  general 
PRINCIPLES.  A  fuller  knowledge  of  these, 
properly  applied,  will  lead  to  better  results 
and  larger  profits. 

CARROLL  B.  SMITH. 
Redlands,  California. 


579459 


Note  :  This  book  has  cross  references  throughout ; 
that  is,  when  a  number  in  parenthesis  follows  a 
sentence  or  paragraph  it  refers  to  some  other  para- 
graph or  sentence  having  the  same  number,  and 
treating  of  the  same  subject.  Any  phase  of  the 
Fertilizer  question  can  thus  be  followed  throughout 
the  book. 


FERTILIZERS: 

Their  Source,  Purchase  and  Use 


SOMETHING  ABOUT  PLANTS. 

CIRCULATION. 

1.  The  higher  plants  (Fruit  and  Forest  trees)  have 
a  well  defined  circulatory  system.  Beginning  with 
the  absorption  by  the  root  , hairs  of  soil  moisture, 
containing  dissolved  plant  food,  one  set  of  tissue 
termed  xylem  carries  this  moisture  or  sap  upward 
into  the  leaves  and  is  there  lost.  In  the  leaf 
the  sap  is  transformed  or  elaborated  largely  by  sun- 
light, according  to  the  plant's  nature  and  needs,  and 
returned  to  the  branches  and  trunk  of  the  tree  and 
its  fruit,  by  another  distinct  set  of  tissue  termed 
phloem.  Both  these  sets  of  tissue  are,  roughly 
speaking,  found  in  the  "Cambium"  or  sap  layer  of 
the  bark.  They  are  between  the  real  bark  and  the 
wood  of  the  tree.  Wood  is  built  up  on  one  side  and 
bark  on  the  other.  In  a  cross  section  of  a  limb  or 
trunk  of  a  tree  these  different  tissues  might  be  illus- 
trated, as  in  Fig.  1. 

The  life  of  the  tree  is  in  the  cambium.  When  we 
bud  or  graft  it  is  cambium  layer  contact  we  want  in 
both  stock  and  scion.  If  the  cambium  is  severed 
completely  around  the  tree  it  dies.  All  of  the  soil 
derived  plant  foods  enter  the  tree  through  its  xylem 
tissue,  found  in  the  cambium  layer. 


FERTILIZERS 


RESPIRATION. 


2.  Plants  have  a  respiratory  system.  They  ab- 
sorb oxygen  and  give  off  carbonic  acid,  mostly  at 
night,  but  during  the  day  more  oxygen  is  given  off 
and  carbonic  acid  absorbed.  The  leaves  and  some  of 
the  green  bark  are  the  respiratory  system.  Carbon 
and  oxygen  thus  enter  the  plant  directly  from  the  air 
as  well  as  by  water  from  the  roots. 


Otctir  -Sa,r4; 


Cow  Ironic 


84  VU 

«     Tf  a 


oocL 


HtArt  Wood 

oieL 


Mi 


FIGURE  1 
TRANSPIRATION. 

3.  Plants  give  off  water  (Transpiration)  at  all 
times  of  day  and  night.  The  water  escapes  at  cer- 
tain pores,  called  Stomata,  of  the  leaf  contained  also 
in  very  young  bark.  Water  carries  the  plant  food 
into  the  plant  by  way  of  the  roots.  The  plant  foods, 
changed  and  elaborated,  are  retained  in  the  tissue  as 
new  growth  while  the  water  passes  off  through 
the  leaves  as  a  vapor.  When  transpiration  exceeds 
the  supply  from  the  roots  the  plant  wilts.  If  the  air 
is  saturated  with  moisture,  plants  give  off  less,  but 


FERTILIZERS  7 

on  hot  days  give  off  more.  The  leaves  of  fruit  trees 
may  be  made  large  or  small  by  an  adequate  or  inad- 
equate supply  of  moisture.  \The  larger  and  healthier 
the  leaves,  the  more  plant  foodjis>laborated~and  the 
better  the  growth  and  the  crop.  So  the  transpira- 
tion system  and  its  healthy  activities  are  very 
directly  connected  with  the  production  of  fruit. 

4.  Any  serious  or  prolonged  check  to  the  process 
of  transpiration  necessitates  a  long  time  for  full 
recovery,  frequently  several  years.  A  severe  wilting 
will  show  for  a  year,  but  a  slight  wilting  usually 
fully  recovers  after  watering.  Thus  the  importance 
of  a  regular  and  sufficient  supply  of  water  is  evident. 

Water  is  the  common  carrier  of  all  the  plant's  food, 
whether  the  food  is  derived  from  the  air  or  from  the 
soil  (13),  the  only  positively  known  exceptions  being 
the  absorption  of  carbon  and  oxygen  by  respiration. 

The  whole  movement  of  water  from  the  root  hairs 
to  the  leaf  and  back  to  other  parts  of  the  plant  and 
fruit,  is  confined  to  the  cambium  layer  in  which  are 
contained  the  xylem  (upward  flow)  and  phloem 
(downward  flow)  tissue. 

LEAVES. 

5.  A  good  leaf  is  essential  to  the  best  results. 
Leaves  put  the  plant  in  communication  with  sun- 
light, under  which  influence  sap  is  changed  and  many 
products,  incident  and  essential  to  growth,  are 
manufactured.  It  is  believed  that  all  of  the  plant 
food  brought  into  the  'tree  by  water,  undergoes 
some  change  in  the  leaf  (digestion)  before  it  is  finally 
added  to  the  various  tissue  of  the  plant.  If  the  leaf 
has  been  stunted  or  impaired  by  drought,  frost  or 
fire,  it  manufactures  less  of  the  products  essential 


8  FERTILIZERS 

to  growth.  Less  water  can  come  into  it ;  therefore, 
less  water  and  less  food  enter  the  plant.  Less  sun- 
light can  act  on  it,  and  all  of  the  activities  of  the 
plant  are  so  reduced  that  the  result  is  a  small  crop 
of  undersized  fruit.  Consequently,  a  good  leaf  is 
essential  to  the  best  results. 

BARK. 

6.  What  has  been  said  of  the  function  of  leaves  is 
true,  to  some  extent,  of  green  bark.  Old,  corky  bark 
may  be  regarded  as  the  armor  or  shield  to  the  cam- 
bium layer.  But  young,  tender  bark  can  carry  on 
the  process  of  respiration  of  carbon  and  oxygen,  and 
of  transpiration  of  moisture,  and  to  that  extent  the 
transformation  of  the  sap  and  plant  food.  Although 
these  activities  in  bark  are  very  limited,  they  are 
sufficient  to  continue  the  life  of  the  tree  should  it 
ever  become  defoliated  for  purposes  of  transplanting 
or  on  account  of  disease  or  frost.  Under  the  young 
bark's  continued  activity  new  leaves  may  start, 
until  finally  the  plant  renews  its  full  health  and 
vigor. 

ROOTS. 

7.  The  distribution  of  plant  food  throughout  the 
soil  influences  directly,  and,  with  water,  the  entire 
development  of  the  root.  The  absorptive  power  of 
the  root  is  in  the  young,  tender  rootlets  or  fibres, 
by  means  of  root  hairs  invisible  to  the  eye.  These 
root  hairs  are  distributed  along  the  length  of  the 
tender,  growing  fibre.  The  end  of  the  fibre  has  a  cap 
which  protects  it  as  it  develops  and  crowds  its  way 
between  the  smallest  soil  particles.  The  very  tips  of 
roots  and  fibres  cannot  absorb  moisture  or  food. 


FERTILIZERS  9 

FIBROUS  ROOTS. 

8.  If  the  soil  is  poor,  the  roots  are  very  long  and 
develop  very  few  fibres  and  root  hairs.  But  in  a 
rich  soil  they  are  short  and  well  branched,  often 
forming  a  perfect  mat  of  fibres.  Under  such  fertile 
conditions  the  root  hairs  are  more  numerous  and  the 
plant's  contact  with  the  soil  and  its  feeding  powers 
are  much  greater.  Consequently,  roots  develop 
where  the  food  is.  Fertilizers  should  be  applied  as 
deep  as  possible,  so  that  root  development  will  not 
be  encouraged  near  the  surface.  (63)  (79). 

SHALLOW   WORK. 

9.  If  the  application  of  fertilizers  and  water  is 
limited  to  the  top  foot  the  most  of  the  fibres  are  de- 
veloped there,  and  deep  ploughing  and  cultivation 
become  questionable  policy.  Thick  water  conserv- 
ing mulch  becomes  impossible,  (see  frontispiece). 
This  is  the  actual  condition  where  impervious  strata 
or  "hard  pan"  lies  near  the  surface. 

DEEP   WORK. 

10.  In  open,  deep  soils  where  water  can  go  down 
easily,  the  plant  food  is  more  widely  distributed  and 
likewise  the  fibrous  roots.  Here,  deep  work  and  a 
deep  mulch  are  possible,  and  in  case  of  water  short- 
age, would  be  found  a  great  advantage,  as  there  is  a 
better  reserve  supply  in  the  sub-soil. 

APPLY  FERTILIZER  DEEPLY. 

11.  Present  practice  applies  all  fertilizer  between 
the  surface  and  the  bottom  of  the  plow  furrow. 
This  is  unavoidable,  even  in  open  soils  where  the 
water   is   easily    absorbed.     Methods    of  effecting 


10  FERTILIZERS 

deeper  applications  without  serious  root  disturbance 
are  unknown.  As  a  result  roots  are  encouraged 
near  the  surface,  and  this  fact  is  the  best  argument 
advanced  for  the  use  of  the  most  water  soluble  forms 
of  fertilizer  obtainable,  as  they  are  more  widely  dis- 
tributed by  the  movement  of  water.  (77)  (79). 

SOILS  AND   ROOTS. 

12.  The  permeable  character  of  the  soil  influences 
the  root  development,  aside  from  the  question  of 
plant  food.  In  clay  or  adcbe  soils  there  is  a  limited 
root  development  and  a  resultant  smaller  tree. 
"Hard  pans"  near  the  surface  have  the  same  limit- 
ing influence.  In  such  soils,  more  trees  can  be 
planted  to  the  acre. 

Open,  free  loams  or  gravelly,  sandy  loams  permit 
a  larger  root  development  and  trees  should  be 
placed  further  apart.  These  are  usually  local  ques- 
tions, but  should  be  considered  by  the  intending 
planter.  The  mechanical  or  physical  nature  of  the 
soil  should  be  known  to  a  considerable  depth.  (20- 
22). 


FERTILIZERS 


SOMETHING  ABOUT  SOILS. 

13.  Of  more  than  seventy  elements  known  to 
chemistry,  fourteen  have  been  found  to  be  essential 
to  plant  life.  Ten  of  these  are  soil  derived,  and  four 
are  derived  from  the  air  : 

Air  Derived.  Soil  Derived. 

Carbon  Calcium 

Oxygen  Silicon 

Hydrogen  Iron 

Nitrogen  Magnesium 

Manganese 
Sulphur 
Chlorine 
Sodium 
Potassium 
Phosphorus 
These  fourteen  elements,  in  varying  portions,  are 
peculiar  to  all  plants  so  far  as  different  species  have 
been  examined. 

14.  All  soils,  for  convenience,  may  be  considered 
as  composed  of  various  portions  of: 


Rock  Powder  \ 
Silt  \ 

Clay 

Humus  ) 

Plant  food       \ 


rSand 


►  or  simply 


Clay 


Humus 


Sand  is  rock  powder  and  may  or  may  not  contain 
silt.  Clay  is  a  chemical  compound  and  a  very  im- 
portant element  of  soils,  as  it  retains  large  amounts 
of  moisture.    If  too  abundant,  the  soil  is  intractable 


12  FERTILIZERS 

and  hard  to  manage,  and  bakes  easily  and  while 
sand  alone  is  too  porous  to  retain  moisture,  the 
addition  of  a  little  clay  with  sand  makes  the  proper 
balance  for  retaining  moisture    and  for   friability. 

15.  Humus,  decayed  organic  matter,  is  absolutely 
essential  as  it  is  the  source  of  the  necessary  nitrogen. 
It  is  a  fundamental  truth  in  connection  with  this  sub- 
ject that  there  is  no  fertility  without  humus.  It  also 
influences  favorably,  as  nothing  else  will,  the  soil's 
mechanical  condition  and  moisture  content,  besides 
supplying  essential  plant  foods. 

The  humus  which  plants  contribute  to  the  soil 
not  only  furnishes  all  of  the  soil  nitrogen,  except 
that  artificially  added,  but  gives  life  to  numerous 
forms  of  bacterial  life,  with  which  every  healthy  soil 
is  teeming.  We  cannot  discuss  this  subject  here  (86- 
89),  but  it  will  suffice  to  say  that,  without  the 
contribution  made  by  plants  to  the  soil,  the  micro- 
scopic forms  of  life  could  not  exist  and  they  are  now 
regarded  as  essential  to  fertility.  Indeed,  it  is  pos- 
sible to  inoculate  soils  with  beneficial  bacteria,  and 
improve  their  fertility. 

A  soil  may  contain  sand,  clay  and  humus  and  yet 
lack  some  essential  plantfood,  hence  the  last  division. 
But  as  a  rule,  sand,  clay  and  humus  in  proper  pro- 
portions will,  for  a  time  at  least,  supply  all  the 
requirements  of  plant  life. 

The  plant  requires  of  the  soil  that  it  furnish  the 
ten  named  soil  derived  elements,  and  the  soil  requires 
of  the  plant  that  it  supply  humus  and  such  of  the 
air  derived  elements  as  are  necessary  to  its  own 
health  and  fertility.  Just  what  amounts  of  hydro- 
gen,  oxygen,  carbon    and    nitrogen    are    absorbed 


FERTILIZERS  1 3 

directly  from  the  air,  and  how  much  is  contributed 
by  plant  life,  is  not  known.  But  it  is  generally  be- 
lieved that  most  of  these  elements  as  found  in  soils 
are  derived  from  plants,  either  through  the  agency 
of  beneficial  bacteria  or  from  the  decay  of  vegetable 
tissue. 

16.  The  character  of  vegetation  changes  with  the 
soil.  Pure  clay  soils  support  very  little  plant  life,  as 
there  is  no  drainage,  no  ventilation  and  no  yielding 
to  root  penetration.  The  right  degree  of  porosity, 
due  to  the  presence  of  sand  and  humus,  allows  the 
roots  to  enlarge  rapidly  which  in  turn  nourishes  a 
large  plant.  Hence  the  same  species  of  plants  will 
vary  in  size  and  appearance  according  as  the  nature 
of  the  soil  encourages  or  restricts  their  growth.  A 
well  developed  root  means  a  well  developed  plant 
and  vice  versa. 

If  potassium  or  sodium  or  chlorine  are  in  excess, 
the  soil  is  alkaline  and  tolerated  by  certain  classes  of 
plants  like  the  salt  bushes,  some  of  the  mallows, 
tussock  grass,  etc. 

Peat  lands,  bogs  and  meadows  have  a  characteris- 
tic vegetation.  Peat  may  contain  as  high  as  80% 
humus  or  decayed  organic  matter.  Here,  nitrogen 
is  naturally  in  excess  and  moisture  plenty,  so  that 
the  growth  is  vigorous  and  succulent.  Tall  grasses, 
and  willows  thrive  here. 

The  well  drained  "mesa"  of  the  arid  west,  sup- 
ports another  variety  of  vegetation  and  a  dense 
forest  cover  or  leaf  mould,  still  another,  according  to 
their  moisture  holding  powers.  The  various  com- 
binations of  sand,  clay,  humus  and  plant  food  are 
almost  infinite. 


14  FERTILIZERS 

17.  Soils  vary  in  chemical  composition  according 
to  depth.  The  surface  foot  or  two  feet  usually  con- 
tains the  bulk  of  the  nitrogen,  due  to  the  fact  that 
the  nitrates  are  water  soluble  and  the  evaporation 
of  moisture  at  the  surface  leaves  the  nitrates  and  all 
soluble  plant  foods  there  for  the  benefit  of  young 
plants  whose  roots  have  not  gone  deep.  Young 
plants  must  grow  first,  and  nitrogen  produces 
growth.  As  the  plant  matures,  its  roots  penetrate 
lower  into  the  region  where  the  nitrogen  is  scarce 
and  where  the  phosphates,  silicon,  lime  and  insoluble 
elements  are  more  evenly  distributed.  There,  fruit 
production  and  maturing  of  tissue  take  place. 

During  the  time  growth  is  vigorous,  fruit  produc- 
tion is  limited  or  impossible  even  in  the  case  of 
mature  trees  when  artificially  forced  to  an  abnor- 
mally vigorous  growth. 

18.  While  nitrogen  is  the  chief  element  of  growth, 
other  elements  of  the  soil  favor  fruit  production. 
Phosphorus  is  definitely  known  to  be  one  of  these. 
(70).  If  the  fruit  producing  elements  of  the  soil  were 
abundant  on  the  surface,  and  nitrogen,  relatively 
deficient  there,  then  fruit  trees  would  be  heavily 
laden  before  they  were  taken  from  the  nursery. 
There  is  abundant  evidence  of  order  and  design  in  the 
methods  of  nature.  "First  the  blade,  then  the  ear, 
then  the  full  corn  on  the  ear,"  and  the  soil  is  so 
arranged  as  to  effect  the  order. 

19.  It  is  interesting  to  note  briefly  that  the  func- 
tion of  potassium  is  to  mature  the  growth  that 
nitrogen  produces.  Where  nitrogen  is  in  excess  of 
potassium,  as  in  bogs  and  peat  lands,  the  growth  is 
soft  and  watery,  whereas  if  potash  is  abundant  and 


FERTILIZERS  15 

the  nitrogen  supply  less,  the  growth  is  hard  and 
firm.  As  illustration :  note  the  strength  of  chap- 
arral wood,  compared  with  marsh  land  growth. 
Nitrogen  is  deficient  (comparatively)  where  the  chap- 
arral grows  and  the  mineral  or  soil  derived  elements, 
including  potassium,  relatively  abundant.  In  a 
word,  potassium  gives  starch  or  stiffness  to  the 
plant.  Young  peppers,  acacias  and  eucalyptus  trees 
bend  frequently  to  the  ground  because  their  roots  are 
in  the  surface  soil,  feeding  on  the  excess  of  nitrogen 
and  water.  Older  trees  with  deeper  roots  have  not 
this  tendency.     (71). 

Sulphur,  iron,  calcium  and  silicon  also  perform 
special  parts  in  the  building  of  plant  tissue,  but  a 
discussion  of  these  would  extend  our  subject  unneces- 
sarily;   Thej-  are  not  "essential"  plant  foods.     (23). 

PHYSICAL    CONDITIONS. 

20.  In  California  the  mechanical  or  physical  con- 
dition of  the  soil  is  of  greater  importance  than  the 
chemical  composition.  Especially  is  this  true  of  cit- 
rus culture,  where  irrigation  and  cultivation  are  so 
frequent  and  thorough.  The  first  sign  of  trouble  is 
usually  a  slight  yellow  color  of  the  foliage  and  is 
usually  traceable  to  loss  of  humus  and  its  conse- 
quent nitrogen.  Yet  the  cause  may  be  due  to  the 
roots  entering  a  "hard  pan"  or  coarse  gravelly 
strata,  less  favorable  to  growth.  (99).  In  any 
event  the  soil's  mechanical  condition  should  be 
known  to  a  depth  of  at  least  five  feet,  and  deeper  if 
possible.  The  loss  of  humus  so  changes  the  soil's 
condition  that  the  trees  cannot  derive  the  benefit  of 
the  water,  the  cultivation  or  the  labor  gives  to  it, 
and  the  first  sign  is  the  loss  of  the  healthy  green  color. 


16  FERTILIZERS 

Applications  of  nitrate  are  helpful  but  not  lasting 
unless  applied  in  organic  forms,  capable  of  making 
humus.     (86)  (96). 

DRAINAGE. 

21.  Citrus  soils  must  be  well  drained.  The  top 
soil  may  be  free  from  gravel  for  a  considerable  depth 
as  long  as  it  does  not  hold  free  water.  The  "mesa" 
or  "  bench "  soils  of  California,  usually  situated 
near  the  foot  hills,  are  ideal  in  this  regard.  Figure  2 
is  a  photograph  of  a  stream  bank,  running  through 
a  "mesa."  The  top  soil,  free  from  rock,  is  here 
about  5  feet  deep,  below  which  there  is  excellent 
drainage. 

HARD    PANS. 

22.  Occasionally  the  best  situation  and  soil  for 
fruit  culture  is  underlaid  at  a  few  feet  with  an  im- 
pervious strata,  so  that  orchards  soon  show  lack  of 
vigor.  These  "hard  pans"  may  be  at  the  very  sur- 
face or  at  any  depth  below.  Blasting  with  powder 
or  dynamite  to  break  up  the  fixed  condition  is  effec- 
tive, but  must  be  repeated  from  time  to  time.  Per- 
haps the  best  remedy  where  water  is  sufficient,  is  to 
prepare  it  long  before  planting  trees,  by  raising  a 
one  or  two  year  old  stand  of  alfalfa,  the  roots  of 
which  penetrate  hard  soils  to  a  considerable  depth. 
Though  the  orchard  is  already  established,  alfalfa 
might  be  grown  in  alternate  spaces  between  the 
tree  rows  for  two  years,  then  ploughed  under  and 
the  remaining  spaces  planted  for  the  next  two  years. 

"  Hard  pans"  are  usually  deficient  in  nitrogen,  but 
may  be  well  supplied  with  the  other  plant  foods, 
and  especially  with  lime  and  iron.  The  latter  gives  a 
very  noticeable  deep  red  tint  to  the  orange. 


FIGURE  2 


FERTILIZERS  1 7 

ESSENTIAL  PLANT  FOOD. 

23.  Each  of  the  three  plant  foods,  nitrogen,  phos- 
phoric acid  and  potash,  are  called  essential  ingredi- 
ents in  fertilizers,  as  they  are  the  elements  first 
exhausted  from  the  soil  by  plants.  There  are  eleven 
other  elements  just  as  essential  to  perfect  plant 
growth  as  these  three,  but  the  soil  never  becomes 
depleted  of  them,  and  it  is  not  necessary  to  supply 
them,  except  in  rare  cases.  Sometimes  lime  is  sup- 
plied to  the  soil,  though  not  regularly,  to  set  free 
nitrogen,  phosphoric  acid  and  potash,  when  they 
are  known  to  be  in  the  soil  in  insoluble  condition 
and  large  amounts.  But,  as  lime  adds  no  necessary 
ingredient,  its  continued  use  alone  will  exhaust  a 
soil.  If  a  soil  is  known  to  lack  iron,  this  may  be 
added  to  make  green  foliage  and  to  deepen  the  color 
of  oranges. 

If  a  soil  becomes  unproductive  under  conditions  of 
good  tillage  and  water,  it  is  usually  because  one  or 
more  of  the  essential  plant  foods  has  become  ex- 
hausted. Hence  commercial  fertilizers  have  come  to 
be  composed  of  various  amounts  and  forms  of  nitro- 
gen, phosphoric  acid  and  potash.  Commercial  fer- 
tilizers are  simply  concentrated  forms  of  plant  food. 
A  good  top  soil  contains  every  element  essential  to 
plant  growth  and  is  a  fertilizer,  but  it  is  not  suffi- 
ciently concentrated  to  pay  for  handling  and  trans- 
portation. 

24.  Each  of  the  three  plant  foods,  nitrogen,  phos- 
phoric acid  and  potash,  have  their  respective  market 
values  for  each  1  per  cent.,  or  unit,  of  20  pounds  to 
the  ton.  If  a  ton  of  fertilizer  contains  3  per  cent,  of 
an  element  that  means  60  pounds.    The  purchaser 


18  FERTILIZERS 

will  have  to  know  in  addition  to  the  amount,  the 
market  value  and  the  source  of  the  nitrogen,  phos- 
phoric acid  and  potash,  before  he  can  determine  the 
value  of  a  ton  of  certain  analysis.  The  source  is 
very  important,  because  the  most  available  forms 
have  the  highest  market  value.  Without  this  know- 
ledge, a  certain  brand  may  sell  for  $40  a  ton  and 
another  worth  only  one-half  its  value  ($20  per  ton) 
may  sell  more  readily  for  $38. 

25.  Each  of  the  three  essential  plant  foods  has 
its  special  part  to  do  in  the  building  of  the  plant. 
One  cannot  do  the  work  of  the  other.  As  an  illus- 
tration: Nitrogen  in  the  absence  of  potash  may 
produce  a  luxuriant  and  rapid  growth  but  it  will 
be  weak,  and  broken  down  by  the  first  wind ;  add 
potash  and  that  same  succulent,  weak  growth  will 
be  matured  and  have  strength  enough  to  carry  its 
load  of  fruit.  Potash  alone  will  not  produce  the 
growth,  but  will  mature  it.  Both  nitrogen  and 
potash  have  manv  other  functions  to  perform.  (69), 
(71). 

Phosphoric  acid,  or  phosphorus,  must  be  present 
in  order  that  the  plant  may  assimilate  its  nitrogen. 
The  process  (osmosis)  by  which  nutrients  pass 
through  the  plant  from  cell  to  cell  is  facilitated  by 
the  presence  of  phosphoric  acid.  Phosphorus  is  nec- 
essary for  the  seed's  embryo  development  and  for  the 
formation  of  chlorophyl  (the  green  coloring  matter 
of  plants).    (70). 

Thus,  while  the  essential  plant  foods  each  have 
many  independent  functions  to  perform,  they  are 
mutually  dependent  upon  each  other,  and  mutually 
helpful  in  the  building  of  the  plant  tissue. 


FERTILIZERS  19 

The  condition  in  the  soil  may  be  such  that  the 
purchase  of  only  one  fertilizing  element  is  necessary, 
and  since  the  source  of  nitrogen  and  phosphoric  acid 
and  their  functions  are  so  many  and  varied,  the 
question,  "What  fertilizer  to  use,"  and  "How  to 
purchase  it  most  economically,"  is  of  vital  interest  to 
the  farmer  and  one  difficult  to  solve. 


SOURCE  OF  FERTILIZERS. 

THE  SOURCE  OF  NITROGEN. 

26.  Nitrogen  may  be  obtained  from  these  sources  : 
Air,  ammonia,  nitrates,  and  animal  matter.  In  certain 
forms  of  animal  matter,  such  as  hoofs,  horns,  coarse 
bone,  leather  and  wool  waste,  the  nitrogen  becomes 
available  too  slowly  to  be  of  much  value.  But  as 
green  manure,  ammonia,  nitrates,  blood,  fine  bone, 
tankage,  or  blood  and  bone,  fish  and  finely  ground 
and  screened  guano,  the  nitrogen  is  in  good  form 
and  soon  becomes  available. 

27.  As  these  forms  require  different  lengths  of 
time  to  become  available,  judgment  must  be  used  in 
their  application.  Nitrate  of  soda  and  sulphate  of 
ammonia  dissolve  almost  immediately  in  water,  so 
the  full  amount  of  a  year's  supply  should  not  be 
applied  at  once,  as  some  will  be  sure  to  be  lost  in 
waste  water.  Blood  and  bone,  as  a  source  of  nitro- 
gen and  phosphoric  acid,  would  be  a  better  combi- 
nation than  nitrate  and  bone.  Blood  and  fish  re- 
quire more  time  to  become  available  than  nitrates, 
and  bone,  a  longer  time  than  blood.    (43) 


20  FERTILIZERS 

The  most  valuable  sources  of  organic  nitrogen, 
from  the  standpoints  of  uniformity  in  composition, 
richness  in  the  constituent,  and  availability,  are  dried 
blood,  dried  meat,  and  concentrated  tankage,  fish 
and  animal,  which  are  produced  in  large  quantities 
in  slaughter  houses  and  fish  canneries. 

28.  The  most  concentrated  form  of  nitrogen  is 
ammonium  sulphate,  containing  about  19%  or  24% 
of  ammonia.  Nitrate  of  soda  contains  as  high  as 
16%  nitrogen,  blood  14%,  hoof  and  horn  meal,  14%, 
slaughter  house  tankage  from  5%  to  10%, raw  bone 
B^%,  bat  guano  3%  to  20%,  sea  fowl  guano  12%. 
There  are  numerous  other  sources  of  nitrogen,  but  the 
above  are  those  most  generally  used.  The  contents 
as  given  are  in  terms  of  nitrogen  and  approximately 
the  maximum. 


SoUtit  7  \  N&u*^ 


-w  *y-  •     \  MZmwowa 

jfc>a.ca.r<cu\  ^ 


FIGURE  3— THE  NITROGEN  CYCLE 


FERTILIZERS  21 

NITRIFICATION. 

29.  This  is  the  process  by  which  the  nitrogen  of 
organic  matter  is  changed  into  nitrates.  The 
ammonia  and  nitrogen  of  all  fertilizers  comes  from 
organic  matter,  and  all  organic  materials  contain 
more  or  less  of  those  substances  in  some  form. 
Nitrate  of  soda  in  the  nitrified  product  of  some 
organic  material,  whether  of  seaweed  or  animals,  is 
not  definitely  known.  Ammonium  sulphate  also 
has  an  organic  origin,  being  a  by-product  of  carbon- 
izing works. 

Humus  (which  is  decayed  animal  or  vegetable 
matter)  is  the  main  source  of  the  plant's  nitrogen. 
When  organic  matter  is  applied  to  the  soil  it  must 
first  decay  and  then  nitrify  before  its  nitrogen  be- 
comes available  to  the  plant.  These  two  processes 
are  necessary.  The  decay  is  produced  by  one  set  of 
bacteria  and  their  product  is  humus.  Then  the  sub- 
stance is  attacked  by  another  set  of  bacteria  which 
form  nitrates.  This  latter  process  is  nitrification. 
The  nitrates  thus  formed  are  water-soluble  and  can 
be  absorbed  by  root  hairs  into  plant  tissue.  (See 
Figure  3.) 

NITROGEN    FROM    AIR. 

30.  Certain  plants  of  the  leguminosae  group  have 
power  to  accumulate  nitrogen  from  the  air  in  the 
process  of  growth.  Such  plants  are  the  lupins  and 
vetches,  which  with  peas,  clover,  alfalfa  and  others, 
when  grown  as  catch  or  cover  crops  and  ploughed 
under,  add  to  the  store  of  nitrogen  in  soils.  But  in 
this  case,  as  with  other  organic  substances,  the  two 
processes  of  decay  of  tissue  and  nitrification,  are  nec- 
essary before  the  nitrogen  thus  gathered  becomes 


22  FERTILIZERS 

available.  As  nitrogen  is  the  most  expensive  of  all 
fertilizing  elements,  the  importance  and  economy  of 
a  green  cover  crop  ploughed  under  is  considerable. 

NITROGEN  FROM  BLOOD  AND  TANKAGE,  GUANO,  ETC. 

31.  The  nitrogen  from  organic  sources  such  as 
blood,  tankage,  guano,  is  prompt  and  decided  in  its 
action  under  ordinary  growing  conditions  if  the 
materials  are  finely  ground.  If  drilled  or  ploughed 
under  with  the  soil  reasonably  moist  and  warm,  the 
effect,  of  added  growth  or  better  color  may  be  seen 
in  30  days.  The  finer  particles  decay  and  become 
available  first,  the  coarser  particles  taking  more 
time.  The  plant  thus  has  a  steady,  long  feeding 
period.  Where  fruit  trees  are  grown  during  a  long 
growing  period  as  in  arid  countries,  the  organic 
forms  of  nitrogenous  fertilizer  are  most  satisfaction-. 

NITROGEN  FROM  NITRATE  OF  SODA. 

32.  This  is  an  immediately  available  form  of  nit- 
rogen. It  dissolves  easily  in  water  and  can  thus  be 
carried  down  to  the  subsoil  and  leached  away  ac- 
cording to  the  course  the  water  takes.  It  is  there- 
fore, not  so  steady  or  long  timed  a  feed  for  plants  if 
it  is  all  applied  at  one  time.  It  is  better,  therefore, 
to  make  at  least  two  applications  during  the  grow- 
ing period.  One  objection  to  its  continued  use,  as 
shown  by  Dr.  King,  is  that  in  time  the  accumulation 
of  the  soda  will  combine  with  the  soil  carbonates 
and  form  carbonate  of  soda  (black  alklai)  which  in 
certain  quantities  is  deleterious  to  all  forms  of  vege- 
tation. Such  a  harmful  accumulation  may  require 
years  but  it  will  finally  become  positive.  Neither 
rains  or  irrigation  will  leach  the  soda  away,  if,  as  it 
is  claimed,  all  the  rains  of  England  have  not  leached 
it  away  from  the  soils  of  Rothampstead  Station. 


FERTILIZERS  23 

SOURCES  OF  PHOSPHORIC   ACID. 

33.  Phosphoric  acid,  or  phosphorus,  in  fertil- 
izers, is  always  found  in  combination  with  other 
elements.  Usually  it  is  obtained  from  bone  or  phos- 
phate rocks.  As  rock  it  cannot  become  readily 
available  without  treatment  with  sulphuric  acid. 
As  bone,  unacidulated,  it  must  be  very  finely  ground 
to  be  available,  and  when  thus  ground  is  undoubt- 
edly the  best  form  for  citrus  culture,  as  it  is  all 
equally  available  and  its  ability  to  rot  or  ferment 
has  not  been  destroyed  by  the  acid.    (40) 

ACIDULATED  PHOSPHATES. 

34.  These  are  made  by  treating  bone  or  phos- 
phate rock  with  sulphuric  acid.  Their  value  may 
vary  according  to  the  amount  of  acid  used  by  the 
manufacturer,  and  the  phosphorus  content  of  the 
mother  rock.  If  800  pounds  of  acid  were  used  with 
1200  pounds  of  bone  or  rock,  it  would  be  a  40% 
acidulation,  as  800  is  40%  of  2000. 

In  acidulated  goods  whether  rock  or  bone,  there 
are  always  three  forms  of  phosphoric  acid — a  soluble 
form,  a  "reverted"  form,  and  an  insoluble  form.  The 
last  is  of  least  "commercial"  value,  but  may  have 
very  great  agricultural  value  under  proper  soil  con- 
ditions. The  "reverted"  is  of  doubtful  value,  as  it 
has  to  first  undergo  a  chemical  change  before  becom- 
ing available.  An  insoluble  portion  is  necessary  in 
order  to  obtain  the  soluble,  but  does  not  add  value 
to  the  fertilizer.  State  laws  allow  the  reverted  to 
be  estimated  as  available  with  the  water  soluble,  so 
that  the  soluble  and  reverted  forms  constitute  the 
commercial  or  "available"  phosphoric  value  of  a  fer- 


24 


FERTILIZERS 


tilizer  but   not  necessarily  the  agricultural  value. 
(67). 

Most  authorities  claim  as  great  a  value  for  the 
insoluble  form,  in  finely  ground  materials,  provided 
there  is  a  normal  or  plentiful  supply  of  humus  in  the 
soil.     (40). 

REVERSION. 

35.  It  must  be  remembered  that  in  using  acidu- 
lated goods  (bone  or  rocks)  if  an  abundance  of  lime 
be  present  in  the  soil,  the  soluble  form  of  phosphoric 
acid  unites  chemically  with  the  lime  and  is  made 
again  insoluble  as  if  it  had  never  been  treated.  Iron 
and  alumina,  and  other  bases,  produce  the  same 
effect  on  acidulated  phosphates.  The  reversion,  how- 
ever, depends  on  the  amount  of  acid  used  by  the 
manufacturer  and  the  quantity  of  lime,  iron,  etc.,  in 
the  soil.    (77). 

"fixing"  power  of  soils. 

36.  The  following  table  will  show  the  "fixing" 
power  of  a  lime  soil : 

PHOSPHORIC  ACID  "FIXED  "  BY  SOIL. 


Kind  of  Soil. 

Grains. 

Grains  of  Soluble 
Phosphoric  Acid 
Used. 

Phosphoric  Acid 
retained   by  the 
Soil. 

Deep  Red) 
Loam      J 

5250 

40.67 

After 

24  hours 

Grains. 

24.29 

8   days 

31.49 

26    days 

38.23 

Lime  soil 

10500 

81.17 

24  hours 

8    days 

26    days 

72.81 
80.31 
81.17 

Even  a  rich  peat  soil,  high  in  either  lime  or  iron, 
will  "fix"  or  hold  phosphoric  acid  in  an  insoluble 
condition,  as  shown  in  49. 


FERTILIZERS  25 

STEAMED  BONE. 

37.  Steaming  bones  removes  the  fat  and  gela- 
tines, thus  facilitating  decay  and  availability,  as 
such  bone  can  be  ground  finer  than  raw  bone,  and 
thus  becomes  more  subject  to  the  attack  of  soil 
moisture  and  various  dissolving  agents. 

Raw  bone  contains  from  3%  to  4*4%  nitrogen  and 
about  22 %  or  23%  phosphoric  acid.  Steaming  re- 
duces the  nitrogen  and  correspondingly  increases 
the  phosphoric  acid,  so  that  steamed  bone  may  run 
as  low  as  1%  nitrogen  and  as  high  as  25%  or  30% 
phosphoric  acid.  The  best  effect  from  the  phos- 
phoric acid  of  steamed  bone  is  had  when  the  bone  is 
used  in  connection  with  some  ammonia te  such  as 
blood,  tankage  or  manure.  Nitrogen  increases  the 
efficiency  of  phosphoric  acid,  and  for  this  reason 
phosphoiic  acid  from  animal  or  vegetable  sources  is 
regarded  as  the  best,  the  most  effective  and  the  most 
readily  available  form.  If  mineral  phosphates  are 
used,  there  must  be  humus  in  the  soil.    (40.) 

THOMAS  PHOSPHATE  SLAG  ( POWDER). 

38.  Thomas  slag,  a  product  from  iron  furnaces, 
is  a  good  source  of  phosphoric  acid,  though  not  so 
generally  used  as  bone  or  rock.  This  material  has 
to  be  finely  ground  to  be  of  value,  as  it  is  not  acidu- 
lated. It  will  analyze  as  high  as  20%  phosphoric 
acid,  usually  17%.  Thomas  slag  also  contains  much 
lime,  which  fact  should  be  considered  when  it  is 
used  in  the  presence  of  ammonium  sulphate,  or 
barn  manures,  as  the  lime  will  drive  off  the  am- 
monia. An  average  analysis  might  show  17.28% 
phosphoric  acid,  46.20%  lime  and  iron  oxide  18.37%. 


26  FERTILIZERS 

It  may  be  used  to  best  advantage  on  trees  which 
have  made  strong,  nitrogenous  growth  at  the  ex- 
pense of  fruit  production,  and  also  on  peaty  soils, 
poor  in  lime.  Water  will  not  dissolve  slag,  there- 
fore it  should  be  put  in  as  deeply  as  possible. 

PHOSPHATE  GUANOS. 

39.  The  guanos  of  bats  and  sea  fowl  are  also 
valuable  sources  of  phosphoric  acid.  These  materi- 
als, however,  vary  in  analysis  very  much.  Each 
consignment  should  be  analyzed  and  its  price  based 
on  its  contents.  The  first  shipments  from  a  guano 
deposit  are  usually  the  richest  and  most  valuable, 
and  may  deteriorate  as  the  deposit  is  drawn  upon. 

CHEAPEST  FORM  OF  PHOSPHORIC  ACID. 

40.  The  Pennsylvania  State  Department  of  Agri- 
culture, in  Bulletin  No.  94,  gives  the  results  of  12 
years'  experiments  with  phosphates,  both  acidu- 
lated and  unacidulated,  and  seems  to  show  conclus- 
ively that  the  best  form  in  which  to  purchase  phos- 
phoric acid  is  the  untreated  bone  or  rock.  This  is 
only  on  condition  that  there  is  plenty  of  organic 
matter,  or  humus-forming  material,  in  the  soil. 

Under  such  conditions  (with  humus  in  the  soil)  finely 
ground  rock  (unacidulated)  gave  better  results  than 
acidulated  rock  or  bone.  This  was  from  the  stand- 
point of  both  original  cost  of  material  and  the 
results  obtained,  and  was  true  of  all  crops  tried, 
except  wheat.  Unacidulated  fertilizers  always  con- 
tain more  phosphoric  acid  than  the  same  fertilizers 
acidulated,  as  the  weight  of  the  acid  used  displaces 
some  of  the  material,  and  if  organic  matter  is  used 
with  the  former,  the  conditions  thus  created  in  the 
soil  give  it  additional  life  which  takes  the  place  of 


FERTILIZERS  27 

acidulation,  and  results  in  greater  fertility.  A  num- 
ber of  lay  experiments  and  actual  practice  in  Call-. 
fornia  agree  with  the  results  of  the  Pennsylvania 
State  Experiment  Station.  Where  there  was  little  or 
no  humus-forming  material  in  the  soil,  acidulated 
forms  gave  the  best  results.  Dr.  Hopkins  of  the 
Illinois  State  Experiment  Station  and  many  others 
strongly  advocate  the  use  of  finely  ground,  unacidu- 
lated  phosphates  with  plenty  of  humus  material, 
rather  than  the  acidulated  forms.   (7),(8),(11). 


SOURCES   OF    POTASH. 

41.  Potash  is  found  as  a  chloride,  or  muriate,  as 
a  sulphate,  and  in  a  crude  form  called  kainit.  The 
latter  contains  121/6%  actual  potash.  The  muriate 
and  sulphate  analyze  about  50%  actual  potash. 
The  Strassfurt  mines  in  Germany  supply  the  most  of 
this  product. 

The  potash  of  manufactured  fertilizers  is  never 
all  animal  matter.  All  commercial  forms  dissolve 
readily,  so  there  is  no  danger  of  buying  potash  in 
unavailable  form.  It  takes  about  two  pounds  of  sul- 
phate, or  muriate  of  potash  to  make  one  pound 
actual  potash,  or  10% sulphate  to  make 5% "actual." 

Wood  ashes  and  stable  manure  are  also  sources  of 
potash,  obtainable,  however,  in  very  limited  quan- 
tities. Wood  ashes,  unleached,  will  contain  from 
42/2%  to  7%  potash:  mixed  stable  manure  contains 
about  0.4%  potash. 

The  sulphate  of  potash  is  the  best  form  in  which 
to  purchase.    It  has  no  ill  effects  on  many  plants, 


28  FERTILIZERS 

while  the  muriate  or  chloride  form  does.  The  sul- 
phate can  also  be  used  as  a  "fixer"  of  ammonia  in 
stables  and  manure  pits,  while  the  muriate  might 
cause  the  escape  of  ammonia. 

AVAILABILITY. 

42.  Buyers  of  fertilizers  should  always  know  the 
source  and  form  of  the  different  plant  foods.  This 
knowledge  and  the  results  obtained  will  determine 
their  availability.  Nitrogen  from  nitrate  of  soda  is 
the  most  available  form  of  any.  Nitrogen  from 
blood  is  more  available  than  that  from  tankage. 

Phosphoric  acid  from  acid  phosphates  (rock  or 
bone)  is  more  soluble  than  the  non-acid  phosphates. 

Steamed  bone  finely  ground  is  more  soluble  than 
raw  bone,  as  the  latter  is  seldom  finely  ground. 

43.  All  nitrogenous  substances  become  available 
easily.  The  most  highly  nitrogenous  are  the  most 
readily  available.  For  this  reason  it  is  difficult  to 
say  whether  steamed  bone  or  raw  bone  as  a  source 
of  phosphoric  acid  is  most  readily  available.  The 
former  is  always  more  finely  ground  and  the  latter 
always  higher  in  nitrogen,  but  as  raw  bone  is  usually 
quite  coarsely  ground,  it  is  less  readily  acted  upon 
by  the  various  dissolving  agents  of  the  soil,  notwith- 
standing its  higher  nitrogen  content.  The  phos- 
phoric acid  from  tankage  is  more  available  than 
that  from  raw  bone.  Both  the  nitrogen  and  phos- 
phoric acid,  as  found  in  animal  tankage  and  guanos, 
finely  ground  are  very  available  forms. 

44.  Soil  moisture,  root  acids  and  fermentation, 
are  the  dissolving  agents  in  all  soils.  The  high  tem- 
peratures of  summer  increase  their  action.  Humus 
is  essential  to  fermentation  and  to  the  carbonic  acid 
in  soil  water  which  is  a  very  active  solvent. 


FERTILIZERS  29 

Roots  cannot  take  up  plant  food  unless  it  is  pro- 
vided in  solution,  and  different  forms  of  fertilizers 
respond  differently  to  these  dissolving  agents.  Fine 
grinding  is  very  important.  As  a  rule  organic  forms 
are  most  available.  There  are  some  exceptions,  such 
as  sulphate  of  ammonia,  nitrate  of  soda,  and  the 
acid  phosphates.  The  latter  act  best  in  soils  that  do 
not  contain  enough  lime,  or  iron,  or  other  bases  to 
cause  rapid  reversion  to  insolubility.     (33)  (34). 

If  the  farmer  knows  the  source  and  form  of  the 
nitrogen  and  phosphoric  acid,  he  has  a  guide  to  their 
availability. 

All  forms  of  potash  as  usually  purchased  in  fertil- 
izers are  readily  dissolved  and  there  is  no  danger  of 
buying  this  ingredient  in  an  insoluble  form. 

45.  Some  substances,  as  lime  carbonate  and 
gypsum,  make  all  fertilizers  more  available  but  they 
do  not  add  plant  food  to  the  soil,  and  their  use  alone 
will  in  time  exhaust  a  soil.  Better  results  will  be 
obtained  by  using  commercial  fertilizers  with  some 
humus  material  than  by  using  either  one  alone, 
because  the  conditions  of  availability  will  be  in- 
creased. 

46.  Probable  order  of  availability,  nitrogenous 
substances : 

Nitrate  of  soda 

Dried  blood 

Tankage  (high  in  nitrogen) 

"         (medium  in  nitrogen) 

"         (low  in  nitrogen ) 
Guanos,  same  as   tankage,  unless    greatly 

nitrified. 
Bone  meal  (finely  ground) 
u        "      (coarse) 


30  FERTILIZERS 

47.  Probable  order  of  availability.    Phosphates  : 

Double  super  phosphate  }  if  watered 
Acidulated  phosphates    )  at  once 
Phosphorus  from  tankage,  high  in  nitrogen. 

"  "     guanos  (as  in  tankage.) 

Thomas  slag 
Steamed  bone  meal 
Raw  "         " 

48.  Probable  order  of  availability.  Potassium, 
(potash)  substances  : 

(  Sulphate 
All  commercial  forms  1  Muriate 

(  Kainit 
Wood  ashes 
Silicates  (natural  soil  forms) 

49.  The  amount  of  potash  and  phosphoric  acid 
carried  by  drainage  and  "run  off"  waters  of  good, 
bad  and  indifferent  soils,  bear  directly  on  this  ques- 
tion of  availability. 

Table  : — "Matters  dissolved  by  water  from  100,- 
000  parts  of  various  soils."  (From  Johnson's  'How 
Crops  Feed.') 


Soils 

Lime 

Mag. 

Pot. 

Phos.  A. 

Silica 

Iron 

Organic 

Total 

Rich 

18 

2 

13 

2 

11 

5 

53 

134 

Good 

34 

7 

8 

— 

22 

— 

36 

136 

Garden 

23 

1.5 

7 

1.5 

38 

2 

30 

110 

Peat 

164 

11 

47 

trace 

trace 

77 

449 

1095 

Poor 

10 

trace 

1 

— 

— 

3 

18 

46 

Fair 

6 

1 

4 

— 

2 

2 

23 

43 

Sandy 

1 

2.5 

2 

trace 

trace 

— 

33 

39.5 

The  matters  least  soluble  are  those  found  in  the 
ash  of  plants.  Where  organic  and  volatile  matter 
is  carried  in  more   appreciable   amounts   there   is 


FERTILIZERS  31 

greater  solubility.  There  is  no  element  less  soluble 
than  Phos.  A.  while  potash  is  present  in  the  drain- 
age water  in  quantity  greater  than  a  trace.  Even 
silica  is  more  soluble  than  phosphoric  acid. 

CONCLUSIONS. 

50.  The  amount  of  soluble  matter  is  greater  in 
wet,  peaty  soils.  Poor  soils  yield  to  water  the  least 
amount.  Very  rich  soils,  and  well  manured  soils 
yield  more  to  water  than  poor  soils.  From  the 
table  it  is  seen  that  where  water  extracted  most 
organic  matter,  it  extracted  large  quantities  of  other 
elements.  Cultivation  and  irrigation  use  up  organic 
matter  rapidly.  So  the  supply  of  humus  materials 
must  be  constantly  renewed.  Humus  and  organic 
matter  are  the  key  to  availability  but  are  also  prob- 
ably the  means  of  exhausting  other  plant  foods 
through  the  production  of  larger  growth  and  crops. 
(86). 

INSOLUBILITY    DESIRABLE. 

51.  It  is  well  known  that  the  nitrates  may  easily 
be  lost  by  leaching,  because  they  are  soluble.  This  is 
not  the  case  with  the  phosphates,  or  phosphorus 
compounds,  as  these  are  always  insoluble  even  in  the 
most  fertile  soils.  Numerous  analyses  of  the  "run 
off"  waters  show  this.  The  nitrates  being  always 
available  to  the  plant,  stimulate  its  feeding  powers 
and  force  it  to  act  on  such  insoluble  compounds  as 
the  phosphates,  which,  in  turn,  by  yielding  slowly, 
regulate  growth  and  maintain  for  a  longer  time  the 
soil's  productive  power. 

It  can  readily  be  seen  that  the  loss  would  be 
many  times  greater  if  the  phosphates  and  other  com- 
pounds were  soluble  as  well  as  the  nitrates. 


32  FERTILIZERS 

The  phosphoric  acid  of  fertile  soils  is  practically 
always  insoluble.  This  is  true  of  new  lands,  the  rich- 
est and  most  productive  known.  It  is  nature's 
method.  All  fertile  soils  contain  such  bases  as  lime, 
iron  and  others  that  hold  phosphorus  in  insoluble 
compounds  from  whence  it  is  released  only  by  the 
processes  of  plant  growth  and  the  chemical  activities 
of  fertile  soils,  due  to  a  sufficient  supply  of  humus. 
(35)  (36). 


THE  PURCHASE  OF  FERTILIZERS. 

52.  Fertilizers  should  be  purchased  by  the  unit  of 
plant  food  contained,  with  due  consideration  of  its 
source,  and  not  simply  by  the  ton  or  brand,  as  is 
usually  the  case.  Each  twenty  pounds  of  a  ton  is 
called  one  unit  or  1%  ;  5%  is  five  units  or  one  hun- 
dred pounds.  The  value  of  a  fertilizer  depends  en- 
tirely upon  the  amount  and  source  of  plant  food  con- 
tained. High  grade  analyses  are  worth  more  than 
low  grade.  Freight,  sacking,  storing  and  handling 
are  fixed  expenses  on  low  or  high  grades.  Therefore, 
high  grades  are  cheapest. 

All  the  simple  forms  of  fertilizer  material,  such  as 
bone  meal,  tankage,  blood,  sulphate  of  potash,  ni- 
trate of  soda,  etc.,  carry  definite  amounts  or  per- 
centages of  their  respective  plant  foods.    (28). 

53.  If,  for  instance,  blood  is  pure  and  cleanly 
handled,  its  nitrogen  content  is  from  13%  to  14%, 
or  260  lbs.  to  280  lbs.  per  ton.  Pure  bone  meal  (raw 
and  steamed)  varies  in  nitrogen  from  1%  to  5%  and 
in  phosphoric  acid  from  20%  to  30%.    If  the  nitro- 


FERTILIZERS  3* 

gen  is  as  low  as  1%  the  phosphoric  acid  will  be 
about  30%.  If  the  nitrogen  is  as  high  as  5%  the 
phosphoric  acid  will  be  about  20%:  and  so  with  all 
the  simple  materials.    Their  limits  are  known. 

It  is  quite  possible  with  these  limits  known,  to  tell 
from  the  guarantee  given  by  a  dealer,  whether  the 
highest  grade  materials  have  been  used  in  a  given 
mixture.  Suppose  a  dealer  guarantees,  as  found  on 
the  bag,  or  tag : 

Nitrogen,  5%  (from  high  grade  blood) 
Phosphoric  acid,  10%  (from  steamed  bone  meal) 
Potash  (K20),  2%  (from  the  sulphate) 
High  grade  blood  contains  at  least  13%  nitrogen 
pure,  or  260  lbs.  to  the  ton.     To  obtain  the  5%  or 
100  lbs.  guaranteed  will  require  |£&  of  a  ton  of  blood 
or  769  lbs. 

The  phosphoric  acid  guaranteed  is  10.%  As 
steamed  bone  meal  may  contain  30%,  to  obtain 
10%  will  require  \%  of  a  ton  or  666.66  lbs. 

Sulphate  of  potash  usually  runs  50  %  actual  (K2O) 
potash,  so  that  the  guarantee  of  2%  or  40  lbs.  could 
be  obtained  from  80  lbs.  of  sulphate.  Altogether  the 
above  guarantee  of:    5%  nitrogen, 

10%  phosphoric  acid, 
2%  potash 
can  be  obtained  from  : 

Blood, 769.     lbs. 

Steamed  bone, 666.66  „ 

Sulphate  of  potash, 80.        ,, 

or,  total  material 1515.66  lbs. 

Make  weight  to  one  ton 484.34   ,, 

2000.001bs. 


34  FERTILIZERS 

The  foregoing  illustration  shows  that  from  a  given 
guarantee  it  is  possible  to  prove  whether  a  full  ton 
of  high  grade  materials  was  used  or  not.  It  would 
be  interesting  also  to  figure  how  much  higher  the 
analysis  would  be  if  the  amounts  of  blood,  bone  and 
sulphate  of  potash  were  increased  proportionately, 
so  that  there  was  no  room  for  "make  weight." 

It  is  only  fair  to  the  dealer  to  say  that  the  484.34 
lbs.  "make  weight"  is  not  necessarily  worthless  filler. 
Low  grade  material  may  have  been  used.  They  are 
offered  in  the  same  market  with  the  best.  Blood  can 
be  so  carelessly  handled  as  to  be  full  of  floor  refuse 
and  foreign  matter.  The  source  of  tankage  influ- 
ences its  grade.  Both  low  and  high  grades  are  legit- 
imately bought  and  sold  in  the  same  market  and  the 
low  grade  often  takes  the  place  of  "filler."  To  make 
the  foregoing  guarantee  without  filler,  we  could 
substitute  1150  lbs.  of  Thomas  slag  for  666.66  lbs. 
of  steamed  bone  meal  so  the  weights  would  be : 
Blood,  769  lbs.  @  13%=  99.9  lbs.  or    5.      % 

Thomas  slag,  1150    "    @18%=207.      "    or  10.25% 

Sulphate  of\        g0    «    @50%=  40*      "    or    2.      % 
Potash        j  ' 

Total  1999  lbs.,  or  no  room  for  filler. 

54.  If  ammonia  is  given  instead  of  nitrogen,  you 
can  find  its  equivalent  in  nitrogen  by  multiplying 
by  .825%;  for  instance,  5.5%  ammonia  equals  4.54% 
nitrogen. 

Do  not  confuse  sulphate  of  potash  with  the  actual 
(or  K2O)  potash.  The  sulphate  usually  runs  about 
50%  actual.  So,  it  takes  2  pounds  of  sulphate  to 
make  one  pound  actual,  or  2%  sulphate  to  make  1% 
actual. 


FERTILIZERS  35 

The  muriate  contains  about  48%  actual  potash 
and  kainit  about  12%. 

Bone  phosphate  must  not  be  confused  with  phos- 
phoric acid.  The  latter  is  derived  from  bone  phos- 
phate and  is  45.8%  of  the  bone  phosphate;  for 
instance,  40%  bone  phosphate =18. 32%  phosphoric 
acid. 

55.  Allowance  must  be  made  for  phosphoric  acid 
if  it  is  derived  from  raw  bone.  It  is  then  worth 
about  2c.  per  pound,  while  if  taken  from  steamed 
bone  would  be  worth  fully  5c.  per  pound.  In  acidu- 
lated goods  the  phosphoric  acid  is  in  three  different 
forms,  with  market  values  from  2c.  up  to  5^.  per 
pound :  the  water-soluble  being  worth  5V£c.  per 
pound,  the  insoluble,  2c.  per  pound.* 

The  source  is  just  as  important  a  consideration 
as  the  quantity  when  considering  the  value.  Both 
the  quantity  of  plant  food  (that  is  of  nitrogen, 
phosphoric  acid  and  potash)  and  its  source,  which 
determines  its  form,  are  really  the  only  factors  which 
compose  the  value  of  a  ton  of  fertilizers.  (67) 


*No  attempt  is  made  to  give  market  values.  These  fig- 
ures are  simply  for  comparison  of  the  different  forms  of 
phosphoric  acid  and  are  those  usually  used  by  State  Agri- 
cultural Stations. 


36  FERTILIZERS 

Here  are  two  analyses  of  different  total  value 
which  will  illustrate  the  foregoing  : 

ANALYSIS  I. 

Nitrogen  in  terms  of  ammonia,  5  % . 
Equivalent  in  nitrogen  (5X.825) 

4.13%  or  82.60  pounds  at  20c $16.52 

Phosphoric  acid  (from  steamed  bone) 

12%  or  240  pounds  at  5y2c 13.20 

Equivalent  to  bone  phosphate  26% 
Potash  (actual,  K20) 

3%  or  60  pounds  at  6c 3.60 

Sulphate  of  potash,  5.9% 

Total  value  of  ton $33.32 

Note. — No  account  is  taken  of  either  the  26%  of 
bone  phosphate  or  of  the  5.9%  sulphate  of  potash  as 
they  are  only  repetitions  of  the  12%  phosphoric  acid 
and  the  3%  actual  potash  respectively. 

ANALYSIS   II. 

Nitrogen  in  terms  of  ammonia,  5M$%. 
Equivalent  to  nitrogen  (5:V2X.825) 

4.54%  or  90.80  pounds  at  20c '. $18.16 

Phosphoric  acid  (from  raw  bone) 

13%  or  260  pounds  at  2c 5.20 

Equal  to  bone  phosphate,  31% . 
Potash,  (actual,  K20) 

4%  or  80  pounds  at  6c 4.80 

Sulphate  of  potash,  7.95%. 

Total  value  of  ton $28.16 

Although  Analysis  II  is  higher  in  its  percentage 

of  plant  food,  the  form  of  the  phosphoric  acid  is 

against  it  and  cheapens  it  so  much  that  the  total 

value  of  the  ton  is  considerably  less. 

Either  of  these  analyses  might  be  offered  to  the 


FERTILIZERS  37 

grower  for,  say,  $35  per  ton  and  No.  1  would  be  the 
best  buy  for  the  grower,  and  No.  2  the  best  sale  for 
the  agent  or  manufacturer. 

It  is  quite  possible  for  the  nitrogen  to  be  in  cheap 
form  also  and  worth  considerably  less  than  20c.  per 
pound.  The  nitrogen  from  raw  bone  is  worth  less 
than  that  from  blood,  or  guano,  or  tankage. 

So  the  value  of  a  ton  of  fertilizer  is  based  upon 
the  source  or  form  of  the  nitrogen,  phosphoric  acid 
and  potash,  and  the  quantity  of  each. 

COST  OF  NITROGEN. 

56.  Nitrate  of  soda,  96%  pure,  16%  nitrogen  at 
$50  per  ton.  This  yields  307  pounds  of  nitrogen, 
which  at  $50  per  ton,  equals  16.3c  per  pound  or 
$3.24  per  unit  of  20  pounds. 

Dried,  ground  blood,  analyzing  14%  nitrogen,  or 
280  pounds  at  $60  per  ton,  equals  21c.  per  pound, 
or  $4.20  per  unit.  Market  values  change  constantly. 
At  times,  nitrate  may  be  worth  $60  and  blood 
worth  $55  per  ton. 

COST  OF  PHOSPHORIC  ACID. 

57.  Steamed,  ground  bone  (not  acidulated)  at 
$35  per  ton,  containing  25%  phosphoric  acid  (500 
pounds  (equals  7c.  per  pound,  less  the  value  of  1  % 
nitrogen  (20  pounds)  contained  in  steamed  bone  at 
20c.  per  pound  would  make  the  net  cost  of  phos- 
phoric acid  about  $1.24  per  20  pounds,  or  6VoC.  per 
pound.  Thomas  Phosphate  Powder,  17%  phos- 
phoric acid,  at  $22.50  per  ton,  would  cost  $1.30  per 
unit,  or  6M$c.  per  pound. 

COST  OF  POTASH. 

58.  The  sulphate  yielding  49%  actual  potash  can 
be  bought  for  $60  per  ton,  making  the  actual  potash 
cost  6c.  per  pound  or  $1.20  per  unit,  (20  pounds). 


38  FERTILIZERS 

COST  OF  COMBINATIONS 

59.  Based  on  the  foregoing,  a  tankage  containing 
5.5%  nitrogen  and  13%  phosphoric  acid  would  have 
value  as  follows : 

5.5%  (units)  nitrogen  @  $4.20  per  unit $23.10 

13%       "       phosphoric  acid  @  $1.24 16.12 

$39.22 

The  nitrogen  and  phosphoric  acid  are  in  much  the 
same  form  as  found  respectively  in  blood  and 
steamed  bone. 

A  guano  containing  5%  nitrogen,  10%  phosphoric 
acid  and  2%  potash,  would  have  a  value  as  follows  : 

5%  (units)  nitrogen,  @ $4.20  (21c.  per  lb. )$  21.00 
10%       "      phosphoric  acid  @  $1.24 12.40 

2%       "      potash®  $1.20 2.40 

$35.80 

MOST  ECONOMICAL  FORM  OF  FERTILIZERS. 

60.  If  the  price  of  nitrogen  is  the  same  in  nitrates, 
and  bone  and  blood,  the  cheapest  is  that  which 
becomes  available  just  as  fast  as  the  crop  requires  it, 
neither  faster  nor  slower.  Is  nitrate  too  quickly 
soluble  for  the  crop  to  use  all  of  it  before  a  part  of  it 
is  carried  away  by  wasted  water  ?  Is  ground  bone 
too  slowly  available  or  blood  and  bone  just  right? 
are  questions  to  be  answered  by  crop  and  con- 
ditions. 

If  a  form  of  plant  food  becomes  available  too 
rapidly,  the  moisture  holding  it  in  solution  rises  and 
evaporates,  leaving  this  soluble,  valuable  food  on 
the  top  of  the  ground,  whence  it  is  partly  lost  by 
escaping  surface  waters  and  part  carried  back  into 
the  soil  by  penetrating  moisture.  That  is  wiry  slow- 
running  water  gives  the  most  profitable  irrigation. 


FERTILIZERS  39 

A  "waste  water"  right  on  one  ranch  from  another 
may  become  also  a  fertilizer  right. 

If,  however,  some  form  of  plant  food,  not  so 
quickly  soluble  in  running  water  as  nitrate  of  soda, 
and  yet  readily  soluble  by  soil  moisture  and  root 
action,  is  used,  there  is  much  less  actual  loss  during 
a  season,  and  its  effect  is  more  sure  and  lasting.  Yet 
there  are  times  when  a  quick-acting  fertilizer  is 
needed.  This  would  then  be  the  most  economical 
form.  It  depends  upon  the  needs  at  the  time,  and 
the  farmer  should  know  enough  about  the  nature  of 
the  different  forms  of  plant  food  to  exercise  judg- 
ment in  the  selection.     (46-48)  (68-71). 

GENERAL  PURCHASING  PRINCIPLES. 

61.  The  market  value  of  every  brand  depends 
upon  the  amount,  or  percentage  of  plant  food  con- 
tained, and  its  form.  The  nitrogen,  phosphoric  acid 
and  potash  each  have  their  own  market  value  per 
pound,  and  these  must  be  known  to  the  grower,  in 
order  to  purchase  economically. 

Be  sure  the  food  elements  are  of  proper  source  and 
form  to  be  available  as  fast  as  wanted  by  the  trees. 
This  availability  depends  upon  soil  conditions. 

Purchase  high  grade  materials. 

EXAMPLE  OF  FERTILIZER  WORTH  $6.50  PER  TON. 

Fresh  water  mud,  2000  pounds,  contains : 

30  pounds  nitrogen  (1V2%)  at  20c $6.00 

4V2    "       phosphoric  acid  (.23%)  at  5 Vac...      .23 

4y2    "       potash  (.23%)  at  6c 27 

$6.50 

EXAMPLE  OF  FERTILIZER  WORTH  $41.10  PER  TON. 

Eighteen  hundred  pounds  of  blood  and  bone, 
containing  7%  nitrogen  and  10%  phosphoric  acid, 


40  FERTILIZERS 

added  to  200  pounds  of  sulphate  of  potash,  will  make 

one  ton,  analyzing  as  follows : 

Nitrogen,6.3  %  or  126  lbs.  @  20c $25.00 

Phosphoric  acid,  9%  or  180  lbs.  @  5V2c...      9.90 

Potash  (K20)  5%  or  100  lbs.  @  6c 6.00 

$41.10 

62.  ILLUSTRATION  NO.  I— A  HIGH  GRADE 

FERTILIZER  CONTAINING  NO  FILLER. 
ANALYSIS.  OBTAINED  FROM  LBS. 

il400  lbs.  raw  bone, 
3.5%  nitrogen 49.00 
400  lbs.  nitrate  soda 
(  96  %  pure  —  16  % 
nitrogen) 61.00 

110.00 

Phosphoric  acid  \frornfl400  lbs  raw  bone  @ 

16%.  /  J23%phosphoricacid..  320.00 

Potash  5  %         \f        (200  lbs.  sulphate  @ 

(100  lbs.) actual)  trom{ 50 factual  potash....  100.00 

COST  OF  ABOVE  MATERIALS. 

1400  lbs.  bone @  $35.00  per  ton $24.50 

400  "  nitrate...®  50.00  "   "  10.00 

200    "    sulphate®    60.00     "      "  6.00 

2000  lbs.  Total $40.50 

ILLUSTRATION  NO.  II— A  LOWER  GRADE  FERTILIZER 

CONTAINING  230  LBS.  FILLER. 
ANALYSIS.  OBTAINED  PROM  LBS. 

/1300  lbs.  raw  bone,  3.5% 

Nitrogen  5%\from  jnitrogen 45.00 

(100 lbs.)   J          J390  lbs.  blood,  14%  nitro- 
gen   54.60 

99.60 


FERTILIZERS  41 

Phosphoric  acid\f        /1300  lbs.  bone,  23% 
15%,  300  lbs.  /lromt phosphoric  acid 299.00 

P°2"h^!lff1)}from:  801bssulPhate 40-00 

COST  OF  ABOVE  MATERIALS. 

1300  lbs.  bone @  $35.00  per  ton..$22.00 

390  "    blood @    50.00  "      "       11.70 

80  "  sulphate  of  potash  @    60.00"       "         2.40 

1770 
230  filler 


2000  lbs.  Total $36.85 

Illustration  No.  I  shows  that  if  the  analysis  is 
high,  only  high  grade  materials  can  be  used.  Illus- 
tration No.  II  shows  that  if  the  analysis  is  low, 
either  low  grade  materials  or  fillers  were  used.  In  No. 
II,  high  grade  materials  up  to  1770  lbs.  were  used, 
and  their  value,  pound  for  pound,  is  the  same  as  in 
No.  I.  A  filler  used  with  high  grade  materials  is 
equivalent  to  the  use  of  low  grade  goods  and  the 
resulting  analysis  in  No.  II  shows  it.  Less  blood 
and  bone  could  have  been  used  in  No.  II,  and  more 
filler,  but  the  resulting  analysis  would  have  been 
still  lower. 

63.  If,  however,  the  fertilizer  is  acidulated,  the  per- 
centage of  plant  food  may  be  low,  as  the  weight  of 
acid  used  displaces  some  of  the  material,  yet  the 
fertilizer  should  be  considered  high  grade  on  account 
of  the  more  soluble  condition  of  its  phosphoric  acid. 
Here,  the  better  form  of  plant  food  compensates  for 
the  smaller  quantity.  If  the  acid  phosphate  should 
revert  to  insolubility  on  account  of  the  lime  or  other 
bases  in  the  soil,  its  purchase  would  be  equivalent  to 
low  grade  materials,  as  the  advantage  of  greater 


42  FERTILIZERS 

solubility  is  largely  lost  and  the  total  amount  of 
phosphoric  acid  purchased  is  small,  yet  its  better 
distribution  in  the  soil  by  water,  may  compensate 
for  reversion.  (8). 

THE  "SIMPLES"  AND  HOME  MIXTURES. 

64.  The  "simples"  are  the  original  materials  or  the 
bases  of  which  factory-mixed  fertilizers  are  composed. 
They  are  such  materials,  as  nitrate  of  soda,  pure 
blood,  sulphate  of  ammonia,  potash,  salts,  bone, 
phosphate  rock,  super  phosphates,  etc.  Tankage 
and  the  guanos  are  "simples,"  as  they  are  the  bases 
of  manufactured  brands.  There  are  low  and  high 
grades  of  the  "simples"  as  well  as  of  brands,  and 
guarantees  should  always  be  obtained  by  the  buyer. 

Sometimes  these  materials  can  be  purchased 
cheaper  separately  than  when  mixed.  Such  is  the 
case  if  the  buyer  is  near  a  seaport  or  near  the  source 
of  the  material.  The  advantages  are,  the  buyer 
knows  what  he  is  getting ;  he  buys  only  the  ingre- 
dients he  needs  and  he  buys  direct.  Such  advantages 
however,  do  not  always  hold  if  the  quantity  wanted 
is  less  than  a  carload. 

If,  however,  a  complete  fertilizer  is  needed,  it  is 
better  to  buy  of  a  reliable  manufacturer,  as  the  goods 
are  then  mixed  and  blended  more  evenly  and  cheaply. 
If  several  ingredients  are  needed  and  these  can  be 
purchased  to  advantage  separately,  it  would  be 
better  to  apply  them  separately  than  to  attempt 
home  mixing,  for  a  shovel  and  a  barn  floor  will  not 
mix  materials  evenly  and  uniformly  without  extreme 
care. 

As  a  rule  home  mixing  pays  when  compared  with 
the  purchase  of  low  grade  brands.    If  the  manufac- 


FERTILIZERS  43 

turer  offers  high  grade  fertilizers  it  is  time  and 
money  saved  to  use  them. 

WHY  THE  ANALYSIS  DOES  NOT  ADD  TO  ONE  HUNDRED 
PER  CENT. 

65.  The  Vermont  Agricultural  Experiment  Sta- 
tion Bulletin  No.  47  says:  "The  question  is  often 
asked  why  the  plant  food  contained  in  a  fertilizer 
does  not  add  up  to  100.  For  instance,  the  average 
Vermont  goods  this  year  contain  in  a  hundred,  2.22 
pounds  nitrogen,  10.93  pounds  total  phosphoric 
acid  and  3.46  pounds  of  potash,  a  total  of  16.61 
pounds.  Of  what  did  the  other  83.39  pounds  con- 
sist, and  is  it  needed  for  plant  food  ?  It  will  be  re- 
membered that  nitrogen  is  a  gas,  and  phosphoric 
acid  and  potash  respectively  strong  acid  and  alkali, 
and  they  can  only  be  useful  in  combined  forms.  If 
medium  grade  materials  were  used  in  the  manufac- 
ture of  the  average  fertilizer,  as  stated  above,  it 
might  be  made  up  as  follows  : 
440  pounds  of  organic  matter  (blood,  tankage,  etc. ) 
850  pounds  of  ground  S.C.  rock  and  sulphuric  acid. 
110  pounds  of  muriate  of  potash. 

1400  lbs. 

This  would  leave  600  pounds,  or  30  per  cent  of 
the  gross  weight  in  every  ton  for  moisture,  dirt  and 
useless  material  on  which  freight,  mixing  and  bag- 
ging expenses,  storage,  etc.,  must  be  paid  by  the 
consumer. 

A  complete  analysis  of  the  above  1400  pounds 
would  probably  resemble  the  following : 


44  FERTILIZERS 

Water 16.0  (combined    with    organic 

matter  and  sulphuric  acid) 

Nitrogen 2.0 

Phosphoric  acid 10.6 

Potash 2.9 

Volatile  and  organic  33.0   (Combined  with  nitrogen) 

Gypsum 16.0  (Formed  by  action    of 

sulphuric  acid  on  rock.) 

Lime 7.1  (Left  combined  with  phos- 
phoric acid) 

Sand 4.0   (Impurity     prosp.     rock.) 

Chlorine  and  Salts..   3.0  (Combined  with  potash.) 

Miscellaneous 5.2 

100.0 

Of  the  ten  substances  which  compose  the  above 
100  per  cent,  only  three  are  of  interest  to  the  farmer. 
The  value  of  the  whole  ton  is  based  on  the  value  of 
the  nitrogen,  phosphoric  acid,  and  potash,  only. 

In  raw  bone,  for  example,  it  is  impossible  to  give 
a  farmer  the  3%  nitrogen  and  the  24%  phosphoric 
acid  contained  without  giving  him  the  73%  of  lime, 
gelatines  and  fats,  etc.,  found  in  bone,  for  these  sub- 
stances are  in  combination  and  the  process  of  separ- 
ation would  be  too  costly. 

HOW  TO  UNDERSTAND  A  FERTILIZER  ANALYSIS 

66.  Manufacturers  often  state  the  analysis  of  their 
fertilizers  in  a  confusing  way.  They  use  two  terms 
to  express  the  same  thing.  Nitrogen  and  ammonia 
both  mean  one  thing,  and  the  analysis  should  read, 
for  example,  "nitrogen  4.95%  equal  to  ammonia 
6%,"  showing  that  there  is  not  both  the  4.95%,  and 
the  6%,  but  only  one  or  the  other.  That  the  one 
repeats  the  other.  Multiply  the  percentage  of  am- 
monia by  .825  and  the  result  will  be  the  equivalent 


FERTILIZERS  45 

in  nitrogen,  as  for  example,  6%  ammonia,  X.825= 
4.95%  nitrogen,  It  takes  4.95%  nitrogen  to  equal 
6%  ammonia.  In  figuring  the  value  of  a  ton  in 
dollars  and  cents,  if  the  nitrogen  from  blood  or 
nitrate  of  soda  has  a  market  value  of  16  cents  per 
pound,  its  equivalent  in  ammonia  is  worth  only 
13M>  cents  per  pound.  Only  one  should  be  included 
in  the  estimate. 

And  so  with  the  terms  bone  phosphate  and  phos- 
phoric acid.  The  phosphoric  acid  comes  from  the 
bone  phosphate.  For  example,  it  takes  30%  of  bone 
phosphate  (sometimes  called  'bone  phosphate  of 
lime')  to  make  13.74%  of  phosphoric  acid.  When 
both  terms  are  employed  by  the  manufacturer 
the  words  "equal  to"  should  be  used  thus:  "Bone 
phosphate  of  lime,  30%,  equal  to  phosphoric  acid, 
13.74%,"  which  means  that  the  manufacturer  used 
600  pounds  of  bone  phosphate  or  bone — 30%  of  the 
ton— to  obtain  13.74%  of  phosphoric  acid. 

Multiply  the  percentage  of  bone  phosphate  by 
.458  and  the  result  will  be  the  equivalent  in  phos- 
phoric acid  thus:  30%  bone  phosphate  of  lime 
X. 458=13. 74%  phosphoric  acid. 

In  estimating  the  value,  for  comparison,  of  a  ton 
in  dollars  and  cents,  phosphoric  acid  from  fine  bone 
is  worth  about  5^ cents  per  pound,  while  its  equiva- 
lent in  terms  of  bone  phosphate  is  worth  only  2V£ 
cents  per  pound.  Only  one  should  be  included  in  the 
estimate. 

Where  the  "soluble,"  the  "reverted,"  and  the 
"insoluble,"  and  the  "total"  phosphoric  acid  are  all 
given,  it  is  understood  that  the  "total"  is  made  up 
of  the  first  three  mentioned. 


46  FERTILIZERS 

The  sulphate  and  muriate  of  potash  will  analyze 
in  round  numbers  about  50%  actual  potash  (some- 
times expressed  as  K2O).  In  other  words  it  takes 
two  pounds  of  sulphate  or  muriate  of  potash  to 
make  one  pound  of  actual  potash  (K2O).  When  an 
analysis  states  :  "Sulphate  of  potash  8%,  actual 
potash  4%,"  it  means  simply  that  there  is  only  4% 
of  actual  potash  in  the  ton,  or  80  pounds,  and  that 
the  manufacturers  used  8%  or  160  pounds  of  sul- 
phate of  potash  to  get  it.  The  actual  potash  is 
worth  about  six  cents  per  pound,  while  the  sulphate 
is  worth  only  three  cents  per  pound. 

When  both  terms  are  used  in  stating  the  analysis, 
only  one  of  them  should  be  included  in  the  estimate 
of  the  value  of  a  ton. 

COMMERCIAL  VS.  AGRICULTURAL  VALUE. 

67.  Farmers  frequently  confound  the  agricultural 
and  commercial  value  of  a  fertilizer.  If  one  is  high 
it  does  not  necessarily  imply  that  the  other  must  be. 

The  commercial  value  of  any  commodity  is  its 
market  price,  its  purchase  price,  and  depends  entirely 
upon  "supply  and  demand." 

The  agricultural  value  of  a  fertilizer  is  its  ability 
to  improve  the  fertility  of  the  soil  and  the  condition 
of  the  crop  in  question. 

As  an  illustration,  suppose  a  steady,  long-lived 
food  were  wanted  for  some  perennials  as  an  orchard, 
blood  would  answer  the  purpose  while  nitrate  of 
soda  would  be  soon  exhausted  or  lost  by  leaching. 
Now,  if  the  price  of  both  nitrate  and  blood  is  about 
the  same,  the  agricultural  value  of  blood  is  far 
greater.  If  a  quickly  acting  manure  was  wanted, 
the  nitrate  of  soda  would  have  the  higher  agricul- 
tural value. 


FERTILIZERS  47 

Again,  if  phosphoric  acid  was  not  needed  for  a 
particular  soil  and  crop,  it  would  then  have  no  agri- 
cultural value  in  that  case,  but  would  still  have  a 
market,  or  commercial  value. 

In  the  selection  of  a  fertilizer,  the  agricultural 
value  should  be  considered  first  and  the  commercial 
value  second.  Good  results  are  of  first  importance 
and  depends  on  the  agricultural  value. 


THE  USE  OF  FERTILIZERS. 

68.  In  order  to  use  fertilizers  intelligently,  it  is 
necessary  to  know  the  specific  action  of  the  three 
plant  foods;  nitrogen,  phosphoric  acid,  and  potash, 
their  sources,  and  when  and  how  to  apply  them. 
The  few  experiments  which  have  been  made  with 
various  fertilizers  on  citrus  trees  confirm  the  same 
general  principles  that  hold  with  reference  to  other 
crops.    They  will  be  briefly  stated. 

EFFECT  OF  NITROGEN. 

69.  The  presence  of  available  nitrogen  is  shown 
by  a  dark,  healthy,  green  color  of  leaves  and  stems. 
Growth  is  vigorous.  The  feeding  power  of  the  plant 
is  increased.  If  an  excess  of  nitrogen  is  available  at 
the  time  of  flowering,  and  the  supply  of  phosphoric 
acid  insufficient,  the  bud  and  bloom  and  fruit  will  be 
imperfect  and  the  total  amount  of  fruit  lessened. 
The  fruit  will  then  be  rough  and  thick-skinned. 
Constant  use  of  stable  manure,  without  the  addition 
of  phosphoric  acid,  will  produce  thick-rind  fruit. 
The  size  of  fruit  may  be  increased  by  nitrogen.    A 


48  FERTILIZERS 

lack  of  nitrogen  is  shown  by  yellow  trees  and 
small  growth,  or  lack  of  vigor.  Nitrogen  will  not 
give  its  best  effect  unless  phosphoric  acid  and  potash 
are  present. 

EFFECT  OF  PHOSPHORIC  ACID. 

70.  Phosphoric  acid  helps  a  plant  to  assimilate 
other  plant  foods.  It  is  also  essential  to  the  final 
maturity  of  the  plant  or  its  seed  production,  and 
hastens  this  maturity,  if  abundant  and  available  at 
blossoming  time.  Although  the  navel  orange  con- 
tains no  seed,  phosphoric  acid  is  as  essential  as 
though  it  did.  What  usually  thus  goes  into  seed  is 
needed  elsewhere  in  the  development  of  the  fruit. 

If  maturity  is  hastened  by  the  presence  of  an 
abundance  of  available  phosphoric  acid  at  the  time 
of  blossom,  the  early  ripening  of  the  orange  can  be 
likewise  effected,  though  plant  food  effects  are 
directly  dependent  upon  culture  and  water. 

Phosphoric  acid  will  not  give  its  best  effect  unless 
there  is  some  nitrogen  present.  Plants  well  supplied 
with  phosphorus,  vegetate  faster  and  are  earlier. 
If  an  over  abundance  of  nitrogen  is  making  fruit 
rough  or  "puffy,"  phosphoric  acid  will  help  to 
correct  this.  Its  tendency  is  to  make  thin-skinned, 
smooth  fruit. 

EFFECT  OF  POTASH. 

71.  Potash  is  necessary  to  the  full  development  of 
the  wood  of  the  tree.  If  potash  is  wanting,  the 
wood  not  only  will  not  mature,  but  is  subject  to 
frost  and  disease ;  neither  can  immature  wood  carry 
much  fruit.  Potash  aids  in  the  formation  and  trans- 
fer of  starch,  first  to  the  leaves  and  from  there  to 
the  flesh  of  the  fruit,  which  would  be  imperfect  other- 


FERTILIZERS  49 

wise.  The  best  authorities  agree  that  potash  in- 
creases the  sweetness  of  fruit  and  their  shipping 
quality.    (19). 

Plants,  undoubtedly,  begin  their  growth  in  the 
spring  on  the  food  that  was  stored  in  their  tissues 
the  previous  fall.  Potash  is  largely  the  source  of 
this  stored  food,  and  is  consequently  necessary  to 
the  full  growth  and  health  of  the  tree. 

It  is  generally  admitted,  however,  that  applica- 
tions of  potash  are  unnecessary  in  most  California 
soils.  Many  cases  are  reported  in  which  heavy 
applications  of  wood  ashes  gave  no  appreciable 
results.  If  the  land  in  question  has  been  continuously 
cropped  many  years,  as  in  a  fifteen  or  twenty  years' 
old  orchard,  the  potash  question  should  be  carefully 
investigated. 

72.  Besides  its  effect  on  the  plant  as  potash  or 
potassium,  increasing  the  starches  and  sugars,  the 
use  of  potash  salts  has  another  indirect  fertilizing 
effect  similar  to  that  of  lime  and  common  salt,  by 
causing  the  soil  to  yield  more  quickly,  its  natural 
and  other  plant  foods.  Potash  salts  while  neutral, 
may  increase  the  alkalinity  of  the  soil  and  thus 
foster  and  encourage  the  work  of  nitrifying  and 
other  bacteria  which  transform  decayed  organic 
matter  into  useful  forms.  Carbon  is  one  of  the  result- 
ant products,  so  that  the  carbonic  acid  which  soil 
moisture  carries,  may  be  increased  thus  making  it 
a  better  solvent  of  many  other  plant  foods.  This 
increased  alkalinity  of  the  soil  may  therefore  increase 
the  formation  of  the  nitrates  and  more  vigorous 
growth  will  result.  Potassium  as  such,  did  not  pro- 
duce this  result,  which  was  due  rather  to  the  added 


50  FERTILIZERS 

alkaline  effect  of  the  potash  salt.  Lime  carbonate  or 
gypsum  or  common  table  salt  might  have  produced 
the  same  effect. 

GENERAL  PRINCIPLES. 

73.  In  a  general  way,  both  phosphoric  acid  and 
potash  influence  the  quality  and  fineness  of  the  fruit, 
while  nitrogen  produces  the  vegetable  tissue,  such  as 
the  skin  and  pulp  of  fruit,  and  leaves  and  bark  of 
trees.  The  juice  and  seed  and  smoothness  and  the 
number  of  the  fruits,  and  earliness,  can  be  increased 
by  phosphoric  acid  and  potash .  The  size  and  coarse- 
ness and  large  growth  and  late  maturity  can  be 
secured  by  the  excessive  use  of  nitrogen.  These  effects 
are  noticeable  only  when  there  is  an  excess  of  one 
element  and  a  deficiency  of  the  others. 

AVOIDING  PURCHASES  OF  UNNECESSARY  FERTILIZERS. 

74.  Knowing  the  specific  effect  of  the  three  essen- 
tial plant  foods,  as  just  stated,  and  by  observing  the 
condition  of  an  orchard,  a  grower  may  frequently 
avoid  the  purchase  of  unnecessary  plant  food. 

Bottom  lands  are  usually  rich  in  nitrogen.  Sandy 
soils  are  apt  to  lack  potash.  Clay  soils  usually  con- 
tain much  potash,  etc.  Coarse,  thick-rind  fruit,  with 
deep  green  color  of  leaves  and  a  too  vigorous  growth 
may  indicate  that  nitrogen  could  profitably  be 
omitted  one  season,  or  used  very  lightly.  An  over 
abundance  of  smooth  fruit  on  yellow  trees  of  slow 
growth  may  indicate  an  excess  of  phosphoric  acid 
for  the  nitrogen  present,  or  a  lack  of  nitrogen.  Iron 
is  as  essential  as  nitrogen  to  green  leaves  and  stems, 
so  yellow  foliage  may,  in  rare  cases,  be  caused  by  the 
absence  of  iron  as  well  as  nitrogen.  The  amount  of 
iron  necessary  for  green  foliage  is  so  small,  that  lack 


FERTILIZERS  51 

of  nitrogen  is  usually  the  cause  of  yellow  color  in 
citrus  orchards. 

A  careful  record  of  previous  applications,  namely  : 
The  amount  and  analysis  of  the  fertilizer,  time  of 
application,  and  its  effects  on  growth  and  crop  will 
be  a  guide  to  selection. 

TIME  TO  APPLY  FERTILIZERS. 

75.  In  the  book  of  nature  we  read  that  growth  is 
dormant  for  some  months  preceeding  the  blossom 
and  fruit  setting  period.  This  is  naturally  the  time 
of  most  moisture  in  soils,  which  with  root  acids  and 
fermentation,  are  rendering  available  the  unavail- 
able plant  foods  natural  to  the  soil.  So,  when  the 
important  time  of  blossom  comes,  the  plants  have 
their  greatest  store  of  available  plant  food  to  draw 
upon,  so  that  fertilizers  should  be  applied  long 
enough  before  the  blossom  time  to  become  avail- 
able. 

76.  Nitrate  of  soda  requires  the  least  time.  Blood 
requires  more  time  than  nitrate,  and  raw  bone  more 
time  than  blood.  Coarse  bone,  and  hoof  and  horn 
meal,  are  slowest  in  their  action.  Acidulated  phos- 
phate acts  more  quickly  than  any  other  form  (that 
is  the  soluble  portion.)  Steamed,  fine  ground  bone, 
used  with  some  ammoniate,  is  next  in  order,  while 
fatty,  raw  bone  takes  still  more  time  to  decompose. 
(46-48). 

Many  apply  a  part  of  the  fertilizer  in  early  sum- 
mer. This  is  intended  to  feed  the  latter  growth  of 
tree  and  crop.  It  is  a  practice  that  undoubtedly 
gives  better  results  and  is  gaining  in  favor. 

77.  Acidulated  forms  should  always  be  applied 
just  before  an  irrigation  or  rain,  for  then  the  water 


52  FERTILIZERS 

will  carry  the  soluble  portion  to  the  deepest  roots, 
wherever,  in  fact  water  can  go.  There,  reversion  to 
insolubility  may  and  probably  does  occur  in  a  few 
days,  but  the  phosphoric  acid  is  where  the  roots  can 
act  on  it  directly.     (8)  (35). 

Nitrate  of  soda  should  not  be  applied  in  late  fall 
or  winter  months  while  growth  is  dormant,  as  it 
would  probably  be  leached  away  before  the  tree  could 
take  it  up.  Organic  forms  should  be  applied  in  Janu- 
ary or  February. 

AMOUNT  TO  APPLY. 

78.  The  quantity  of  fertilizer  that  should  be  used 
varies  with  the  conditions.    It  depends  upon  : 

1.  The  percentage  richness  of  the  fertilizer. 

2.  Record  of  past  experience. 

3.  Natural  richness  of  soil. 

4.  Age  and  number  of  trees  per  acre. 

5.  Kind  of  tree  or  crop. 

One  popular  way  of  estimating  the  amount  to  use 
is  to  say  one  pound  of  high  grade  fertilizer  to  each 
year  of  age  of  the  tree.  This,  while  very  inaccurate, 
gives  good  results,  but  the  practice  of  citrus  culture 
has  demonstrated  the  wisdom  of  using  considerably 
more  than  this  amount,  probably  two  pounds  for 
each  year  of  age  of  citrus  trees  will  be  fully  war- 
ranted in  most  cases. 

This  is  particularly  true  of  trees  over  twelve  and 
fifteen  years  old.  If  the  fertilizer  is  low  grade,  the 
amount  used  should  be  increased. 

If  trees  have  been  topped  for  budding  or  very 
severely  pruned,  the  amount  may  be  reduced  accor- 
dingly. 


FERTILIZERS  53 

METHODS  OF  APPLICATION. 

79.  The  best  method  of  application  is  undoubt- 
edly by  drill,  on  account  of  its  labor  saving  and 
uniformity. 

Though  not  over  five  inches  deep,  the  drill  covers  the 
fertilizer,  which  can  be  placed  deeper  by  subsequent 
plowing.  The  use  of  drill  obviates  the  unpleasantness 
of  applying  in  any  winds  which  may  prevail.  No 
hand  process  is  so  uniform  or  inexpensive,  though 
some  other  methods  place  the  fertilizer  deeper.  It  is 
well  worth  the  extra  cost  to  hire  a  hand  to  follow 
each  plow  furrow  and  place  the  fertilizer  that  depth. 

STABLE  MANURE. 

80.  An  average  analysis  of  one  ton  of  horse 
manure  would  be  : 

Nitrogen— 0.50%  or  10  lbs.  of  a  ton  at  20c $2.00 

Phosphoric  acid — 0.25%  or  5  lbs.  of  a  ton  at  6c.     .30 

Potash— 0.40%  or  9.6  lbs.  of  a  ton  at  6c 58 

$2.88 
The  commercial  value  of  the  plant  food  is  then 
about  $2.88  per  ton.  Barn  yard  manure  when  cared 
for  properly,  is  a  most  profitable  form  of  fertilizer, 
because  of  its  humic  and  mulch  value.  It  is  a  bi- 
product  of  every  ranch,  costs  nothing,  and  is  worth 
about  $2.88  per  ton  for  the  actual  plant  food  con- 
tained. In  dry  countries  it  has  a  still  greater  value 
in  its  moisture  saving  properties.  As  a  source  of 
humus  it  is  worth  considerably  more  than  its  plant 
food  value. 

81.  The  more  decomposed  the  manure,  the  more 
available  is  its  plant  food.  If,  however,  decomposi- 
tion is  too  rapid,  the  nitrogen  escapes  in  the  air  as 
ammonia,  and  humus-forming  matter  is  destroyed. 


54  FERTILIZERS 

High  temperatures  produce  rapid  decomposition, 
especially  in  a  loose  heap,  so  that  the  rate  of  decay 
maybe  regulated  by  compacting  the  heap  and  sprink- 
ling with  water  to  exclude  the  air  and  reduce  the 
temperature.  If  compacted  too  tightly,  decomposi- 
tion may  be  too  slow.  Moderate  fermentation  is  the 
object  desired.  Loss  of  nitrogen,  as  ammonia,  may 
be  detected  by  the  strong  odor  arising,  from  the  heap. 

If  it  is  desired  to  obtain  the  benefits  of  the  plant 
food  in  manure  quickly,  it  should  be  stored  under 
cover  to  prevent  loss  by  leaching,  and  the  tempera- 
ture kept  down  by  frequent  wetting,  and  air  ex- 
cluded by  settling  the  heap :  decomposition  may 
thus  take  place  with  a  minimum  loss  of  ammonia. 
If  from  one  to  two  pounds  of  either  gypsum,  or  sul- 
phate of  potash  be  sprinkled  on  the  heap  each  day 
as  it  accumulates  from  one  or  two  animals,  the  am- 
monia is  converted  to  the  sulphate  form  and  thus 
prevented  from  escaping.  The  gypsum  must  be 
moist  for  this  use  to  be  effective. 

If,  however,  it  is  not  desired  to  get  the  benefits  of 
plant  food  quickly,  the  manure  had  better  be  applied 
fresh  and  incorporated  with  the  soil  at  once.  Decom- 
position may  be  slower  in  such  cases,  but  loss  of 
ammonia  is  surely  prevented  and  a  much  better 
mulch  obtained.    This  is  the  most  practical  method. 

GREEN  MANURING. 

82.  The  object  of  sowing  the  leguminous,  or  pod- 
bearing  plants  is  chiefly  four-fold. 

1.  For  humus,  which  is  always  necessary  for  any 
form  of  crop  because  of  its  various  functions  in  the 
soil,  such  as  :  (a)  nitrification  ;  (b)  Rendering  insol- 
uble forms  of  plant  food  available  by  the  process  of 


FERTILIZERS  55 

decay,  (29)  ;    (c)  Increasing    the    moisture    holding 
power  and  friability  of  the  soil.    (90.) 

2.  To  obtain  the  nitrogen  which  they  gather 
during  their  growth.    (30). 

3.  To  set  free  unavailable  plant  foods  by  the 
direct  action  of  their  roots.  (Insoluble  substances 
are  coroded,  and  dissolved  and  taken  up  into  the 
plant  tissue  and  later  become  available  as  the  plant 
decays.) 

4.  To  prevent  soil  washing  and  leaching  by  win- 
ter rains. 

83.  The  common  vetch  (Vicia  Sativa)  is  at  pres- 
ent the  most  popular  legume  for  the  California  orch- 
ardist.  Field  peas,  some  clovers,  and  other  varieties 
of  vetch  are  also  used.  Barley  and  other  non  legu- 
minous plants  have  not  the  same  nitrogen  gather- 
ing power  but  are  beneficial  as  far  as  their  roots  set 
free  unavailable  forms  of  potash  and  phosphoric 
acid. 

The  volunteer  non-leguminous  plants  and  weeds 
such  as  alfilerea  mallow,  foxtail  and  others,  are  per- 
haps as  beneficial  as  legumes  plants  for  their  humus 
value  and  root  petetration  and  while  it  is  not  cer- 
tainty known  just  now  how  much  nitrogen  may  be 
added  by  various  legumes  it  is  probably  safe  to 
assume  that  they  add  some  and  for  this  reason  are 
preferred  to  the  non-leguminous  plants. 

COVER  CROPS  AND  WATER. 

84.  It  is  well  known  that  the  winter  cover  crops 
use  up  a  good  portion  of  the  rain  that  falls  so  that 
comparatively  the  clean  culture  orchards  begin  the 
dry  season  with  more  moisture  in  the  ground.  While 
this  loss  is  usually  more  than  compensated  for  by 


56  FERTILIZERS 

the  many  advantages  of  the  cover  crop  already 
cited  there  may  be  special  situations  where  the 
water  is  all  necessary  to  the  orchard.  If  the  water 
right  were  limited  by  the  capacity  of  the  ditch  or  if 
the  season's  rainfall  were  too  short  to  risk  the  loss 
of  water  necessary  to  a  cover  crop,  straw  or  dam- 
aged hay  could  be  hauled  and  spread  and  plowed 
under  as  a  fair  substitute.  Any  amount  of  humus 
could  be  added  in  this  way  and  all  of  the  rainfall  con- 
served for  the  summer  months. 

SUMMER  COVER  CROPS. 

85.  It  is  difficult  to  maintain  the  supply  of  humus 
material  under  conditions  of  constant  irrigation  and 
cultivation.  Cover  crops  have  been  raised  in  sum- 
mer as  well  as  in  winter  in  a  few  instances.  Horse 
beans  and  cow  peas  have  been  used  for  the  purpose. 
They  are  planted  in  May  or  June  and  turned  under 
in  August,  and  while  the  results  are  undoubtedly 
beneficial  the  extra  water  necessar}'  will  prevent  the 
practice  from  becoming  general. 

The  United  States  Government  has  found  by  ex- 
periment in  California  orchards,  several  legumes  that 
promise  a  greater  tonage  of  green  matter,  under 
equal  conditions,  than  the  present  Oregon  or  com- 
mon vetch  so  generally  used.  These  include  two 
species  of  Vicia;  one  pea,  and  one  bean.  So  that 
this  phase  of  agriculture  will  no  doubt  be  improved 
and  modified  from  time  to  time. 

The  green  manure  wanted  by  orange  growers  is 
one  that  will  grow  quickly  as  California  winters  are 
short  and  dry,  and  growers  cannot  afford  to  let  the 
ground  rest  undisturbed  very  long. 


FERTILIZERS  57 

HUMUS  FERTILIZERS-NECESSITY  OF 
ORGANIC  MATTER. 

86.  Humus  is  decayed  organic  matter.  It  is  neces- 
sary for  fertility,  because  all  the  nitrogen  in  soils 
comes  from  either  an  animal  or  vegetable  source. 
(Very  minute  quantities  are  absorbed  from  the  air 
as  ammonia  and  as  nitrogen).  The  nitrates  come 
from  humus.  They  are  water  soluble  and  can  be 
taken  up  by  the  roots.  Thus  the  plant  gets  its 
nitrogen.    (15)  (29) 

All  fertile  soils  are  rich  in  organic  matter.  The  ex- 
ceeding richness  of  new  lands  is  due  to  the  humus 
deposited  by  succeeding  crops  for  generations.  This 
is  true  of  both  the  high  mesa  and  the  valley  land. 
It  is  possible  to  use  some  chemical  form  of  nitrogen 
and  raise  a  plant,  but  it  is  expensive,  requires  close 
watching  and  is  not  practical.  The  nitrogen  from 
organic  fertilizers  is  yielded  to  the  plant  gradually, 
with  greater  certainty,  and  is  more  lasting. 

87.  Organic  manures,  whether  of  blood  and  bone, 
or  stable  manure,  or  green  cover  crops,  not  only 
furnish  nitrogen  to  plant  life,  but  their  decay  gen- 
erates several  well  known  acids,  notably  carbonic, 
which  combine  with  the  soil  moisture  and  dissolve 
other  forms  of  plant  food.  Without  these  acids, 
phosphorus,  potash  and  other  necessary  elements 
would  not  be  so  available  to  the  plant.  Direct  root 
and  water  action  would  then  have  to  do  the  work 
alone,  and  the  plant  would  not  thrive  so  well.  Hu- 
mus influences  the  availability  of  the  phosphoric 
acid  and  potash  and  converts  them  into  forms  more 
readily  utilized  by  the  plant.     (49-50). 


58  FERTILIZERS 

88.  Organic  fertilizers  lighten  soils.  Their  decay 
leaves  the  soil  open  and  porous.  More  oxygen  is 
thus  admitted,  which  gives  more  life  to  the  micro- 
organisms, which,  after  all,  are  the  cause  of  all  fer- 
tility. Better  cultivation  is  possible  in  such  soils. 
Light,  porous  soils  are  more  retentive  of  moisture. 
Thus,  organic  matter  literally  builds  up  a  soil.  It 
increases  its  depth.  A  "worn-out"  soil  is  simply  a 
soil  devoid  of  humus.  It  is  lifeless.  Liberal  applica- 
tions of  organic  matter  restore  it  and  change  it  from 
a  tax  to  an  income. 

89.  Humus  forming-materials  are,  therefore, 
necessary  to  successful  and  practical  farming.  The 
best  results  from  inorganic  fertilizers,  such  as  rock 
and  acid  phosphates,  Thomas  slag  and  sulphate  of 
potash,  are  obtained  when  they  are  used  with  ma- 
nure, or  blood,  or  blood  and  bone,  or  a  green  cover 
crop  turned  under. 

90.  "Humus  is  not  only  the  principal  source  of 
nitrogen  in  soils,  but  it  influences  to  a  marked  ex- 
tent the  available  potash  and  phosphoric  acid. 
Humus  forming  materials,  like  green  manures  and 
yard  manure,  have  the  power,  when  they  decompose 
in  the  soil,  of  combining  with  the  potash  and  phos- 
phoric acid  of  the  soil  and  thus  converting  them  into 
forms  which  are  readily  utilized  by  the  plants.  "(82). 


CULTIVATION  AND  FERTILIZERS. 

91.  Cultivation  increases  the  availability  of  fer- 
tilizers by  aiding  nitrification  and  by  saving  soil 
moisture.  All  organic  forms  must  first  decay  and 
then  be  turned    into  nitrates    (nitrification),    and 


FERTILIZERS  59 

other  salts  before  water  can  carry  their  elements  to 
the  roots  of  plants.  (29). 

The  decomposed  matter  (humus)  is  attacked  by 
nitrifying  bacteria  and  these  require  oxygen  for 
their  work.  Cultivation  increases  this  supply  of 
oxygen  so  that  nitrification  proceeds  faster,  and 
better  growth  results.  The  more  frequent  and  deep 
the  cultivation,  the  better  the  nitrifying  bacteria  can 
work.  The  size  of  fruit  can  be  increased  in  this  way, 
or  a  short  season  made  equal  to  a  long  one. 

Cultivation  therefore  uses  up  humus  very  rapidly 
so  that  the  supply  must  be  frequently  renewed.  The 
extra  growth  and  yield  are  probably  proportional 
to  the  supply  of  humus  and  frequency  of  cultivation. 

92.  This  principle  of  aiding  nitrification  applies 
to  all  forms  of  animal  and  vegetable  fertilizers  such 
as  yard  manure,  blood,  raw  bone,  guano,  tankage, 
and  peas  and  clover,  planted  for  their  fertilizing 
value  when  ploughed  under. 

Frequent,  deep  cultivation  increases  the  supply 
of  water  in  soils.  Several  well-known  acids,  result- 
ing from  decomposition,  unite  with  soil  moisture 
and  dissolve  what  ordinary  water  will  not.  Insol- 
uble forms  of  fertilizers,  such  as  phosphate  of  lime 
and  silicate  of  potash,  are  probably  thus  made 
available  to  the  plant. 

93.  Moist  soils  swell  and  are  more  permeable. 
Roots  can  develop  faster  in  them,  and  the  fertilizers, 
applied  to  the  top,  six  inches,  as  they  gradually  dis- 
solve, can  be  carried  more  easily  and  deeply,  increas- 
ing the  feeding  area  of  the  roots  and  the  develop- 
ment of  the  plant. 

Frequent  and  through  cultivation,  helps  and 
multiplies  these  beneficial  effects  of   soil  moisture. 


60  FERTILIZERS 

IRRIGATION  AND  FERTILIZERS. 

94.  Plants  can  take  up  food,  only  when  it  is  pro- 
vided in  solution.  The  food  may  be  dissolved  by 
water,  or  by  direct  root  action,  or  by  the  process  of 
fermentation,  which  is  almost  constant  in  all  soils. 
In  either  case  water  is  essential,  and  the  common 
carrier,  and  the  way  in  which  it  is  used,  seriously 
effects  the  results  of  fertilization.  Especially  is  this 
true  because  the  top  foot  of  soil  contains  the  most 
valuable  fertilizing  ingredients. 

There  are  three  kinds  of  water  in  soils  :  free  water 
which  moves  by  gravity  ;  hygroscopic  water,  detect- 
able only  by  laboratory  methods  even  in  the  dryest 
earth,  and  capillary  water,  which  moves  by  the 
power  of  attraction  between  particles  of  matter. 
This  capillary  water  is  what  plants  feed  and  depend 
upon  mainly.  It  travels  up  and  down  freely  with 
very  little  motion,  sideways,  carrying  with  it  the 
soluble  fertilizers. 

95.  It  is  useless  to  apply  fertilizers  on  dry  ground 
that  is  not  dampened  by  irrigating  water,  as  for 
instance  ;  far  under  very  old  trees  or  on  the  midway 
spaces  in  young  orchards  where  furrows  are  not 
made. 

As  moisture  evaporates  at  the  surface,  it  is  con- 
stantly supplied  from  below  by  the  capillary  move- 
ment. The  dissolved  fertilizers  contained,  remain  at 
the  surface  from  which  the  water  evaporates  ;  hence 
they  accumulate  so  that  top  soils  are  always  the 
richest.  The  next  rain  or  irrigation  carries  the  plant 
food  down  only  to  rise  again  as  evaporation  pro- 
gresses at  the  surface.  There  is  thus  an  oscillation 
of  water  containing  many  kinds  of  plant  food,  up 
and  down  many  times  a  year. 


FERTILIZERS  61 

96.  Certain  forms  of  fertilizers,  such  as  the  ni- 
trates (both  soda  and  potash)  ammonium  sulphate, 
the  sulphate  of  potash,  and  the  acid  and  super-phos- 
phates are  easily  carried  by  water.  If  applied  just 
previous  to  an  irrigation  they  go  to  the  deepest 
roots,  or  wherever  water  can  go.  If  there  is  any 
waste  water  a  part  of  them  is  lost. 

If  the  grade  from  the  flume  is  very  steep  for  fifty 
feet  or  more,  the  trees  in  that  space  will  be  the  first 
to  turn  yellow,  although  they  are  nearest  the  flume 
and  receive  the  most  water.  The  nitrates  have  been 
washed  to  lower  levels.  Manure  or  straw  should  be 
used  in  such  places  so  that  the  water  will  move 
more  slowly  and  the  nitrates  retained  where  they 
belong. 

On  account  of  the  solubility  of  many  forms  of 
plant  food,  irrigation  water  should  be  handled  very 
carefully.  Do  not  turn  a  heavy  head  of  water  into  a 
furrow  until  after  the  furrow  is  soaked  a  little  and 
the  fine  earth  compacted.  This  will  lessen  washing. 
The  ideal  movement  of  water  is  up  and  down,  with 
as  little  movement  on  the  surface  as  possible.  In 
this  way  the  rich  top  soil  with  its  humus  and  fer- 
tilizers will  be  retained  where  it  belongs. 

VALUE  OF  SOIL  ANALYSIS. 

97.  Soil  anatyses  are  valuable  for  determining  in 
a  general  way  the  needs  of  a  crop.  The  greater  the 
number  of  samples  examined,  the  more  accurate  will 
be  the  information  obtained.  Very  little  can  be  con- 
cluded from  one  sample.  Taken  in  connection  with 
the  appearance  of  trees  and  vegetation  raised  on  the 
soil,  many  a  useless  expenditure  for  fertilizing  ingre- 
dients may  thus  be  avoided. 


62  FERTILIZERS 

If  samples  of  soil  be  taken  according  to  the  direc- 
tions of  the  State  Experiment  Station  the  results 
may  be  relied  upon  as  indicating  that  soil's  capacity 
for  various  crops.  This  information,  with  the 
owner's  knowledge  of  previous  treatment,  together 
with  the  appearance  of  the  vegetation  and  growth 
gives  a  pretty  thorough  diagnosis.  Each  of  these 
sources  of  information  acts  as  a  check  or  supple- 
ments the  other  two. 

98.  Soil  analysis  should  be  interpreted  by  an  ex- 
pert for  where  y^  of  1  %  would  be  considered  a  suffic- 
iency of  some  element,  it  would  be  regarded  as  a 
deficiency  of  other  elements.  A  soil  containing  %  of 
1%  humus  is  lacking  in  that  substance,  while  that 
amount  of  potash  or  lime  would  be  considered 
ample  for  fertility.  (100). 

Again,  soil  analyses  may  reveal  the  presence  of 
some  poison,  such  as  carbonate  of  soda,  or  chlorine, 
in  the  midst  of  otherwise  fertile  conditions,  An  ex- 
cess of  either  acid  or  alkali  can  likewise  be  deter- 
mined. Plant  food  may  be  present  in  abundance  and 
yet  the  results  be  unsatisfactory  on  account  of  poor 
cultural  conditions,  or  lack  of  humus.  This,  also, 
soil  analysis  would  reveal. 

Whenever  there  is  uncertainty  about  the  needs  of 
crops  or  orchard,  soil  analysis  should  always  be 
taken.  One  element,  only  may  be  lacking  and  thus 
discovered,  and  the  purchase  of  the  element  unneces- 
sary be  avoided.  The  California  State  Experiment 
Station  has  advised  farmers  that  sufficient  potash  is 
present  in  nearly  all  California  soils.  General  experi- 
ence has  confirmed  this  statement,  thus  saving  the 
farmers  many  dollars  annually. 


FERTILIZERS  63 

99.  The  mechanical  analysis  of  soils  is  always 
important.  Most  California  soils  are  sedimentary 
and  composed  of  irregular  strata  varying  in  thick- 
ness from  a  few  inches  to  many  feet.  They  may  be 
impenetra table  and  poorly  drained,  or  too  open  and 
coarse  to  hold  the  requisite  moisture.  The  subsoil 
conditions  should  be  known.     (20-21-22). 

100.  The  following  table  is  compiled  mainly  from 
the  records  of  the  California  State  Experiment  Sta- 
tion and  from  Dr.  Hilgard's  book,  "Soil,"  which 
state  quite  positively  that  when  the  chemical  deter- 
mination of  certain  elements  in  soils  run  below  a 
certain  amount  that  soil  is  quite  sure  to  be  unpro- 
ductive. These  figures  are  the  result  of  a  large  num- 
ber of  analyses  representing  years  of  work. 

ADEQUATE  PLANT  FOOD. 


RICH 

ADEQUATE 

INADEQUATE 

PER  CENT. 

PER  CENT. 

PER  CENT. 

Humus  in  soil         2.00 

1.00 

0.85 

Nitrogen  in  humus  9.00 

4.00 

2.00 

Lime                          1.50 

1.00 

0.40 

Phosphoric  acid     0.20 

0.10 

0.05 

Potash  (K20)         1.00 

0.45 

0.25 

These  figures  will  vary  for  different  crops.  Ade- 
quacy for  one  kind  of  crop  might  be  inadequate  for 
another.  But  they  are  averages  for  a  large  number 
of  determinations  and  very  suggestive.  It  has  been 
well  established  also  that  when  the  per  cent,  of  lime 
is  high,  much  smaller  amounts  of  the  other  plant 
foods  will  suffice. 


64  FERTILIZERS 

FERTILIZING  VALUE  OF  STRAW,  STABLE  MANURE, 
ORANGE  CULLS,  AND  CERTAIN  LEGUMES,  f 


101. 

N. 

P.  A.        Pot.* 

JPea  vine  hay 

3.00 

$12.00 

$  Vetch  hay 

2.55 

10.20 

Burr  clover  hay 

2.68 

10.72 

Alfalfa  hay 

2.19 

1.51         1.68 

11.37 

Wheat  straw 

0.59 

0.12         0.51 

3.12 

Stable  manure 

0.50 

0.25        0.50 

2.87 

Orange  culls 

0.18 

0.12        0.21 

1.10 

•(Nitrogen  @  $4.00  per 

unit.  Phos.  acid  @  $1.00 

per  unit  and  potash  @  $1.25  per  unit.) 

fThe  value  of  the  above  materials  for  humus  is 
probably  equal  to,  or  greater  than  their  fertility 
value  as  judged  by  the  results  obtained  from  their 
use. 

$It  is  assumed  in  the  table  that  the  pea,  vetch  and 
burr  clover  were  raised  as  a  cover  catch  crop  in  the 
orchard,  and  that  this  nitrogen  is  all  gain,  which 
fact  is  not  yet  established  beyond  doubt.  Their 
phosphoric  acid  and  potash  are  not  reported,  as 
what  they  take  of  these  from  the  soil  is  returned 
with  them. 


INDEX. 

Acidulated  Phosphates 23 

Adequate  plant  food 63 

Agricultural  value 46 

Alfalfa,  fertilizing  value  64 

Analysis  adding  to  100  per  cent 43 

Analysis  of  fertilizer.    How  to  understand 44 

Analysis  of  soil 61 

Applying  fertilizers,  Time  for 51 

Applying  fertilizers,  Amount 52 

Applying  fertilizers,  Method 53 

Applying  fertilizers  deeply 9 

Availability 28 

Availability,  Order  of 29 

Basic  slag 25 

Bone 25 

Burr  clover,  fertilizing  value 64 

Canadian  peas,  fertilizing  value 64 

Commercial  value 46 

Clover  crops  and  water 55 

Culls,  fertilizing  value 64 

Cultivation,  relation  to  fertilizers 58 

Drainage  of  soils 16 

Economical  form  of  fertilizers 38 

Effects  of  plant  foods 50 

Essential  plant  food 17 

Example  of  fertilizer  worth  $6.50  per  ton 39 

Example  of  fertilizer  worth  $41.10  per  ton 39 

Fertilizers,  purchase 32 

Fertilizers,  source 19 

Fertilizers,  use 47 

General  principles,  effect  of  fertilizers 50 

Green  manure 54 

High  grade  fertilizer,  example 40 


INDEX. 

Home  mixtures 42 

Humus  (organic  matter) 57 

Insolubility,  desirable 31 

Irrigation,  relation  to  fertilizers 60 

Lower  grade  fertilizers,  example 40 

Manure,  green     54 

Manure,  stable 53 

Manure,  fertilizing  value 64 

Most  economical  form 88 

Nitrification  21 

Nitrogen,  cost  of   37 

Nitrogen,  effect  of 47 

Nitrogen,  from  air 21 

Nitrogen,  sources  of 19 

Nitrogen  from  organic  sources 22 

Nitrogen  cycle 20 

Nitrate  of  soda  and  carbonates 22 

Orange  culls 64 

Organic  matter  (humus) 57 

Peas,  green  manure 54 

Phosphate  guanos 26 

Phosphoric  acid,  cheapest  form 26 

Phosphoric  acid,  cost  of 37 

Phosphoric  acid,  effect  of 48 

Phosphoric  acid,  sources  of 23 

Plants,  general 5 

Plant  food,  amount  necessary 63 

Plant  food 11 

Plant  food  "essential" 17 

Plant  food,  air  derived II 

Plant  food,  soil  derived 11 

Plant  food,  definition 17 

Potash,  effect  of 48 


INDEX. 

Potash,  cost  of 37 

Potash,  sources  of 27 

Purchasing,  general  principles 39 

Purchase  of  fertilizer 32 

Roots 8 

Reversion  of  phosphates 24 

"Simples" 42 

Soil  analysis,  value  of 61 

Soils,  composition  of 11 

Soils,  fix  phosphorus 24 

Soils,  drainage  of 16 

Soils,  physical  condition 15 

Source  of  fertilizers 19 

Solubility  in  different  soils 30 

Stable  manure 53 

Steamed  bone 25 

Straw,  fertilizing  value 64 

Summer  cover  crop  56 

Thomas  phosphate  slag 25 

Unnecessary  fertilizers,  avoiding  purchase 50 

Use  of  fertilizers  47 

Vetch,  common,  fertilizing  value 64 

Vetch,  green  manure 54 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 

Los  Angeles 

This  book  is  DUE  on  the  last  date  stamped  below. 


OK  1  4  1954 
JUNIUS*"! 


Form  L9-25m-9,*47(A5618)444 


s 

633 

S61i3f 

1911 


